ROGER

MacBRIDE

ALLEN

To five wondrous creatures, named in the order of their appearance on this planet:

Aaron

Victoria

Benton

Jonathan

And

Meredith

Acknowledgments

            This book would not have been possible without the support, and especially the patience, of David Harris, John Betancourt, Byron Preiss, Susan Allison, Ginjer Buchanan, and Peter Heck.  There was many a slip between cup and the lip, but thanks to their collective efforts, never a drop of the good stuff was lost.  The book stands as proof once again that every writer needs at least one editor, and sometimes five or six is no bad idea.  Thanks are also due to Thomas B. Allen and Eleanore Fox, neither of whom had time to read the manuscript, and both of whom did.

I

A Robot May Not Injure a Human Being, or, Through Inaction, Allow a Human Being to Come to Harm.

II

A Robot Must Obey the Orders Given It by Human Beings Except where Such Orders Would Conflict with the First Law.

III

A Robot Must Protect Its Own Existence As Long As Such Protection Does Not Conflict with the First or Second Law.

            ...THE Spacer-Settler struggle was at its beginning, and at its end, an ideological contest. Indeed, to take a page from primitive studies, it might more accurately be termed a theological battle, for both sides clung to their positions more out of faith, fear, and tradition than through any carefully reasoned marshaling of the facts.

            Always, whether acknowledged or not, there was one issue at the center of every confrontation between the two sides: robots. One side regarded them as the ultimate good, while the other saw them as the ultimate evil.

            Spacers were the descendants of men and women who had fled semi-mythical Earth with their robots when robots were banned there. Exiled from Earth, they traveled in crude starships on the first wave of colonization from Earth. With the aid of their robots, the Spacers terraformed fifty worlds and created a culture of great beauty and refinement, where all unpleasant tasks were left to the robots. Ultimately, virtually all work was left to the robots. Having colonized fifty planets, the Spacers called a halt, and set themselves no other task than enjoying the fruits of their robots’ labor.

            The Settlers were the descendants of those who stayed behind on Earth. Their ancestors lived in great underground Cities, built to be safe from atomic attack. It is beyond doubt that this way of life induced a certain xenophobia into Settler culture. That xenophobia long survived the threat of atomic war, and came to be directed against the smug Spacers--and their robots.

            It was fear that had caused Earth to cast out robots in the first place. Part of it was an irrational fear of metal monsters wandering the landscape. However, the people of Earth had more reasonable fears as well. They worried that robots would take jobs--and the means of making a living--from humans. Most seriously, they looked to what they saw as the indolence, the lethargy and decadence of Spacer society. The Settlers feared that robots would relieve humanity of its spirit, its will, its ambition, even as they relieved humanity of its burdens.

            The Spacers, meanwhile, had grown disdainful of the people they perceived to be grubby underground dwellers. Spacers came to deny their own common ancestry with the people who had cast them out. But so, too, did they lose their own ambition. Their technology, their culture, their worldview, all became static, if not stagnant, The Spacer ideal seemed to be a universe where nothing ever happened, where yesterday and tomorrow were like today, and the robots took care of all the unpleasant details.

            The Settlers set out to colonize the galaxy in earnest, terraforming endless worlds, leapfrogging past the Spacer worlds and Spacer technology. The Settlers carried with them the traditional viewpoints of the home world. Every encounter with the Spacers seemed to confirm the Settlers’ reasons for distrusting robots. Fear and hatred of robots became one of the foundations of Settler policy and philosophy. Robot hatred, coupled with the rather arrogant Spacer style, did little to endear Settler to Spacer.

            But still, sometimes, somehow, the two sides managed to cooperate, however great the degree of friction and suspicion. People of goodwill on both sides attempted to cast aside fear and hatred to work together--with varying success.

            It was on Inferno, one of the smallest, weakest, most fragile of the Spacer worlds, that Spacer and Settler made one of the boldest attempts to work together. The people of that world, who called themselves Infernals, found themselves facing two crises. Their ecological difficulties all knew about, though few understood their severity. Settler experts in terraforming were called in to deal with that.

            But it was the second crisis, the hidden crisis, that proved the greater danger. For, unbeknownst to themselves, the Infernals and the Settlers on that aptly named world were forced to face a remarkable change in the very nature of robots themselves...

--Early History of Colonization, by Sarhir Vadid,

Baleyworld University Press, S.E 1231

THE blow smashed into her skull.

            Fredda Leving’s knees buckled. She dropped her tea mug. It fell to the floor and shattered in a splash of brown liquid. Fredda crumpled toward the ground. Her shoulder struck the floor, smashing into the broken shards of the cup. They slashed into her left shoulder and the left side of her face. Blood poured from the wounds.

            She lay there, on her side, motionless, curled up in a ghoulish mockery of the fetal position.

            For the briefest of moments, she regained consciousness. It might have been a split second after the attack, or two hours later, she could not say. But she saw them, there was no doubt of that. She saw the feet, the two red metallic feet, not thirty centimeters from her face. She felt fear, astonishment, confusion. But then her pain and her injury closed over her again, and she knew no more.

            ROBOT CBN-001, also known as Caliban, awoke for the first time. In a world new to him, his eyes switched on to glow a deep and penetrating blue as he looked about his surroundings. He had no memory, no understanding to guide him. He knew nothing.

            He looked down at himself and saw he was tall, his body metallic red. His left arm was half-raised. He was holding it straight out in front of him, his fist clenched. He flexed his elbow, opened his fist, and stared at his hand for a moment. He lowered his arm. He moved his head from side to side, seeing, hearing, thinking, with no recollection of experience to guide him. Where am I, who am I, what am I?

            I am in a laboratory of some sort, I am Caliban, I am a robot. The answers came from inside him, but not from his mind. From an on-board datastore, he realized, and that knowledge likewise came from the datastore. So that is where answers come from, he concluded.

            He looked down to the floor and saw a body lying on its side there, its head near his feet. It was the crumpled form of a young woman, a pool of blood growing around her head and the upper part of her body. Instantly he recognized the concepts of woman, young, blood, the answers flitting into his awareness almost before he could form the questions. Truly a remarkable device, this on-board datastore.

            Who is she? Why does she lie there? What is wrong with her? He waited in vain for the answers to spring forth, but no explanation came to him. The store could not--or would not--help him with those questions. Some answers, it seemed, it would not give. Caliban knelt down, peered at the woman more closely, dipped a finger in the pool of blood. His thermocouple sensors revealed that it was already rapidly cooling, coagulating. The principle of blood clotting snapped into his mind. It should be sticky, he thought, and tested the notion, pressing his forefinger to his thumb and then pulling them apart. Yes, a slight resistance.

            But blood, and an injured human. A strange sensation stole over him, as he knew there was some reaction, some intense, deep-rooted response that he should have--some response that was not there at all.

            The blood was pooling around Caliban’ s feet now. He rose to his full two-meter height again and found that he did not desire to stand in a pool of blood. He wished to leave this place for more pleasant surroundings. He stepped clear of the blood and saw an open doorway at the far end of the room. He had no goal, no purpose, no understanding, no memory. One direction was as good as another. Once he started moving, there was no reason to stop.

            Caliban left the laboratory, wholly and utterly unaware that he was leaving a trail of bloody footprints behind. He went through the doorway and kept on going, out of the room, out of the building, out into the city.

            SHERIFF’S Robot Donald DNL-111 surveyed the blood-splattered floor, grimly aware that, on all the Spacer worlds, only in the city of Hades on the planet of Inferno could a scene of such violence be reduced to a matter of routine.

            But Inferno was different, which was of course the problem in the first place.

            Here on Inferno it was happening more and more often. One human would attack another at night--it was nearly always night--and flee. A robot--it was nearly always a robot--would come across the crime scene and report it, then suffer a major cognitive dissonance breakdown, unable to cope with the direct, vivid, horrifying evidence of violence against a human being. Then the med-robots would rush in. The Sheriff’s dispatch center would summon Donald, the Sheriff’s personal robot, to the scene. If Donald judged the situation warranted Kresh’ s attention, Donald instructed the household robot to waken Sheriff Alvar Kresh and suggest that he join Donald at the scene.

            Tonight the dismal ritual would be played out in full. This attack, beyond question, required that the Sheriff investigate personally. The victim, after all, was Fredda Leving. Kresh must needs be summoned.

            And so some other, subordinate robot would waken Kresh, dress him, and send him on his way here. That was unfortunate, as Kresh seemed to feel Donald was the only one who could do it properly. And when Alvar Kresh woke in a bad mood, he often flew his own aircar in order to work off his tension. Donald did not like the idea of his master flying himself in any circumstances. But the thought of Alvar Kresh in an evil mood, half -asleep, flying at night, was especially unpleasant.

            But there was nothing Donald could do about all that, and a great deal to be done here. Donald was a short, almost rotund robot, painted a metallic shade of the Sheriff’s Department’s sky-blue and carefully designed to be an inconspicuous presence, the sort of robot that could not possibly disturb or upset or intimidate anyone. People responded better to an inquisitive police robot if it was not obtrusive. Donald’s head and body were rounded, the sides and planes of his form flowing into each other in smooth curves. His arms and legs were short, and no effort had been made to put anything more than the merest sketch of a human face on the front of his head.

            He had two blue-glowing eyes, and a speaker grille for a mouth, but otherwise his head was utterly featureless, expressionless.

            Which was perhaps just as well, for had his face been mobile enough to do so, he would have been hard-pressed to formulate an expression appropriate to his reaction now. Donald was a police robot, relatively hardened to the idea of someone harming a human, but even he was having a great deal of trouble dealing with this attack. He had not seen one this bad in a while. And he had never been in the position of knowing the victim. And it was, after all, Fredda Leving herself who had built Donald, named Donald. Donald found that personal acquaintance with the victim only made his First Law tensions worse.

            Fredda Leving was crumpled on the floor, her head in a pool of her own blood, two trails of bloody footprints leading from the scene in different directions, out two of the four doors to the room. There were no footprints leading in.

            “Sir--sir--sir?” The robotic voice was raspy and rather crudely mechanical, spoken aloud rather than via hyperwave. Donald turned and looked at the speaker. It was the maintenance robot that had hyperwaved this one in.

            “Yes, what it is?”

            “Will she--will she--will she be all--all right right?” Donald looked down at the small tan robot. It was a DAA-BOR unit, not more than a meter and a half high. The word-stutter in his speech told him what he knew already. Before very much longer, this little robot was likely to be good for little more than the scrap heap, a victim of First Law dissonance.

            Theory had it that a robot on the scene should be able to provide first aid, with the medical dispatch center ready to transmit any specialized medical knowledge that might be needed. But a serious head injury, with all the potential for brain damage, made that impossible. Even leaving aside the question of having surgical equipment in hand, this maintenance robot did not have the brain capacity, the fine motor skills, or the visual acuity needed to diagnose a head wound. The maintenance robot must have been caught in a classic First Law trap, knowing that Fredda Leving was badly injured, but knowing that any inexpert attempt to aid her could well injure her further. Caught between the injunction to do no harm and the command not to allow harm through inaction, the DAA-BOR’s positronic brain must have been severely damaged as it oscillated back and forth between the demands for action and inaction.

            “I believe that the medical robots have the situation well in hand, Daabor 5132,” Donald replied. Perhaps some encouraging words from an authority figure like a high-end police robot might do some good, help stabilize the cognitive dissonance that was clearly disabling this robot. “I am certain that your prompt call for assistance helped to save her life. If you had not acted as you did, the medical team might well not have arrived in time.”

            “Thank thank thank you, sir. That is good to know.”

            “One thing puzzles me, however. Tell me, friend--where are all the other robots? Why are you the only one here? Where are the staff robots, and Madame Leving’s personal robot?”

            “Ordered--ordered away,” the little robot answered, still struggling to get its speech under greater control. “Others ordered to leave area earlier in evening. They are in are in the other wing of the laboratory, And Madame Leving does not bring a personal robot with her to work.”

            Donald looked at the other robot in astonishment. Both statements were remarkable. That a leading roboticist did not keep a personal robot was incredible. No Spacer would venture out of the house without a personal robot in attendance. A citizen of Inferno would be far more likely to venture out stark naked than without a robot--and Inferno had a strong tradition of modesty, even among Spacer worlds.

            But that was as nothing compared to the idea of the staff robots being ordered to leave. How could that be? And who ordered them to go? The assailant? It seemed an obvious conclusion. For the most fleeting of seconds, Donald hesitated. It was dangerous for this robot to answer such questions, given its fragile state of mind and diminished capacity. The additional conflicts between First and Second Laws could easily do irreparable harm. But no, it was necessary to ask the questions now. Daabor 5132 was likely to suffer a complete cognitive breakdown at any moment in any event, and this might be the only chance to ask. It would have been far better for a human, for Sheriff Kresh, to do the asking, but this robot could fail at any moment. Donald resolved to take the chance. “Who gave this order, friend? And how did you come to disobey that order?”

            “Did not disobey! Was not present when order given. Sent--I was sent--on an errand. I came back after.”

            “Then how do you know the order was given?”

            “Because it was given before! Other times!”

            Other times? Donald was more and more amazed. “Who gave it? What other times? Who gave the order? Why did that person give the order?”

            Daabor 5132’s head jerked abruptly to one side. “Cannot say. Ordered not to tell. Ordered we were ordered not to say we were sent away, either--but now going away caused harm to human harm harm harm--”

            And with a low strangling noise, Daabor 5132 froze up. Its green eyes flared bright for a moment and then went dark.

            Donald stared sadly at what had been a reasoning being brief moments before. There could be no question that he had chosen rightly. Daabor 5132 would have failed within a few minutes in any event.

            At least there was the hope that a skilled human roboticist could get further information out of the other staff robots.

            Donald turned away from the ruined maintenance robot and turned his attention back toward the human victim on the floor, surrounded by the med-robots.

            It was the sight that had destroyed the Daabor robot, but Donald knew he was, quite literally, made of sterner stuff. Fredda Leving herself had adjusted his First, Second, and Third Law potential with the express purpose of making him capable of performing police work.

            Donald 111 stared at the scene before him, feeling the sort of First Law tension familiar to a sheriff’s robot: Here was a human being in pain, in danger, and yet he could not act. The med-robots were here for that, and they could aid Fredda Leving far more competently than he ever could. Donald knew that, and restrained himself, but the First Law was quite clear and emphatic: A robot may not injure a human being, or, through inaction, allow a human being to come to harm. No loopholes, no exceptions.

            But to aid this human would be to interfere with the work of the med-robots, thus at least potentially bringing harm to Fredda Leving. Therefore, to do nothing was to aid her. But he was enjoined against doing nothing, and yet to aid her would be to interfere--Donald fought down the tremors inside his mind as his positronic brain dealt with the same dissonance that had destroyed Daabor 5132. Donald knew that his police-robot adjustments would see to it he survived the episode, as he had so many in the past, but that did not make it any less unpleasant.

            Humans, on the other hand: These days, the sight of blood and violence scarcely bothered Alvar Kresh. Human beings could get used to such things. They could adapt. Donald knew that was so intellectually, he had observed it, but he could not understand how it was possible. To see a human in distress, in danger, to see a human as the victim of violence, even dead, and to be unmoved--that was simply beyond his comprehension.

            But human or robot, the police saw a lot, especially on Inferno, and experience did make it easier in some ways. The paths of his positronic brain were well worn with the knowledge of how to deal with this situation, however disturbing that might be. Stay back. Observe. Gather data. Let the meds do their work.

            And then wait for the human, wait for Alvar Kresh, wait for the Sheriff of the city of Hades.

            The med-robots worked on the still form, rushing to stabilize her, ensure her blood supply, patching up the gashes in her shoulder and face, attaching monitor pads and drug infusers, moving her to a lift stretcher, shrouding her in blankets, inserting a breather tube into her mouth, cocooning her from sight behind their protections and ministrations. And that is how it should be, Donald thought. Robots are the shield between humans and the dangers of the world.

            Though the shield had clearly failed this time. It was a miracle that Fredda Leving was even alive. By all appearances the attack had been remarkably violent. But who had done this, and why?

            The observer robots hovered about, recording the images of this scene from every angle. Maybe their data would be of some use. Let them soak in all the details. Donald shifted his attention to the two sets of bloody footprints that led from the body. He had already tracked them out as far as they went. Both sets of prints faded away into invisibility after only a hundred meters or so, and he let it go at that. Police technical robots were already using molecular sniffers to try to extend the trails, but they wouldn’t get anywhere. They never did.

            But there was no missing the key fact, the vital piece of evidence. And no denying the horrible, unthinkable conclusion they suggested.

            Both sets of footprints were robotic. Both sets. Donald, designed, programmed, trained in police work, could not avoid making the obvious and terrifying inference.

            But it could not be. It couldn’t be.

            Donald devoutly wished for Alvar Kresh to arrive. Let a human take over, let someone who could get used to such things deal with the impossible thought that a robot could have struck Fredda Leving from behind.

            THE night sky roared past Sheriff Alvar Kresh, and the scattered lights of buildings in Hades’s outskirts gleamed bright below. He looked up into the dark sky and saw the bright stars glowing down at him. A beautiful night, a perfect night for a speed run over the city, something he only got the chance to do on official business, and he had to be in a foul mood.

            He did not care for being awakened in the middle of the night, did not care for anyone but Donald helping him to dress.

            He tried to cheer himself up, to soothe himself. He looked out into the night. Tonight was the best weather Hades had had in a long time. No sandstorms, no dust-haze. There was even a fresh tang of seawater blowing in off the Great Bay.

            At least he could burn off his adrenaline and his anger by flying his aircar himself, rather than leaving the chore to a robot. He took a certain pride in that. Few humans even knew how to fly an aircar. Most people felt the chore of controlling an aircraft beneath them. They let the robots do it. No doubt most people thought it was damned odd that Alvar liked to fly his own car. But few people were likely to say that to the Sheriff’s face.

            Alvar Kresh yawned and blinked, and punched the coffee button on the aircar’s beverage dispenser. He was alert, clear-eyed, but there was still a shroud of tiredness over him, and the first sip of the coffee was welcome. The aircar sped on through the night as he flew it one-handed, drinking his coffee. He grinned. Lucky Donald isn’t here, he thought. It was stunts like flying one-handed that made it all but impossible for him to fly his own car when Donald, or indeed any robot, was on board. One false move and the robot would instantly leap into the copilot’s seat and take over the craft’s controls.

            Ah, well. Maybe the Settlers sneered at robots, but no Spacer world could function for thirty seconds without them. That having been said, the damned things could be incredibly infuriating all the same.

            Alvar Kresh forced himself to calmness. He had been roused from a sound sleep in the dead of night, and he knew from bitter experience that interrupted sleep made him more edgy than usual. He had learned long ago that he needed to do something to take the edge off himself when he was too keyed up, or else he was likely to take someone’ s head off instead.

            Alvar breathed the cool thin air. A nightflight over the desert at speed with the top open and the wind howling through his thick thatch of white hair helped drain away some of his temper, his tension.

            But crimes of violence were still rare enough in Hades for him to take them personally, to get angry and stay that way. He needed that anger. This savage and cowardly attack on a leading scientist was intolerable. Maybe he did not agree with Fredda Leving’s politics, but he knew better than most that neither the Spacer worlds in general nor Inferno in particular could afford the loss of any talented individual.

            Alvar Kresh watched as the city swept by below him, and began to slow the aircar. There. The aircar’s navigation system reported that they were directly over the Leving Robotics Labs. Alvar peered over the edge of the car, but it was difficult to get a fix on the precise building at night. He eased the car to a halt, adjusted its position over the landscape slightly, and brought it down to the ground.

            A robot ground attendant hurried over to the car and opened the door for him. Alvar Kresh stood up and stepped out of the car, into the night.

            There was a busy rummaging-about going on. A red and white ambulance aircar squatted on the ground near Kresh’s car, its lift motors idling, its running lights on, obviously ready to lift off the moment its patient was aboard. A squad of med-robots bustled through the main door of the lab, two of them carrying a stretcher, the others holding feed lines and monitoring equipment hooked up to the patient. Leving herself was not quite visible under the tangle of life-support gear. A human doctor lounged by the hatch of the ambulance, watching the robots do the work. Alvar stood still and let the robots pass as they carried the victim from the scene of the crime.

            He watched, his anger rising inside him, as the meds carried her into their van, and watched as the indolent human doctor eased his way into the ambulance behind his busy charges. How could anyone commit such violence against another human being? he asked himself.

            But raw, unchanneled anger would not help catch Fredda Leving’s assailant. Remain calm, he thought. Keep your anger controlled, focused. Alvar Kresh lifted his hand to a med-robot that was carrying a first-aid kit back to the ambulance. “What is the condition of your patient?” he asked.

            The gleaming red and white med-robot regarded Kresh through glowing orange eyes. “She received a severe head injury, but no irreparable trauma,” it said.

            “Were her injuries life-threatening?” Kresh asked.

            “Had we been delayed in reaching Madame Leving, her injuries could easily have been fatal,” the robot said, a bit primly.

            “However, she should recover completely, though there is the distinct possibility that she will suffer traumatic amnesia. We shall place her in a regeneration unit as soon as we reach the hospital.”

            “Very good,” Kresh said. “You may go.” He turned and watched the last of the med team climb into the ambulance and take off into the night. Good that she would recover, but it could be very bad indeed if she did suffer amnesia. People with holes in their memories made for bad witnesses. But the words of the med-robots changed the nature of the case. Her injuries could easily have been fatal. That changed a simple assault with a deadly weapon case into one of attempted murder. At last he turned to go inside the building, to see what Donald and his forensic team had come up with.

“ALL right, Donald,” Kresh said as he came in, “what have you got?”

            “Good evening, Sheriff Kresh,” Donald replied, speaking with a smooth and urbane courtesy. “I am afraid we do not have a great deal. The crime scene does not tell us much that we can use, though of course you may well note something we have missed. I have not been able to form a satisfactory interpretation of the evidence. Did you have the opportunity to examine my update regarding the maintenance robot’s statements?”

            “Yes, I did. Damn strange. You did right to get the data out of him, but I don’t want to take any chances on the rest of the staff robots. I don’t even want to get near them myself. I want the department’s staff roboticists to interview them all--carefully.” Normally the police roboticists dealt with robots who had been tricked into this or that by con artists skilled in lying to robots and convincing them to obey illegal orders under some carefully designed misapprehension. A man could make a pretty fair living convincing household robots to reveal their masters’ financial account codes. It would do the roboticists good to deal with something a little out of the ordinary.” But we can worry about that tomorrow. Is the scene clear?”

            “Yes, sir. The observer robots have completed their basic scan of the area. I believe you can examine the room without danger of destroying clues, so long as you practice some care.”

            Alvar looked closely at Donald. After a lifetime of dealing with robots, he still did that, still looked toward the machines as if he could read an emotion or a thought in their expressions or postures. On some robots, on the very rare ones that mimicked human appearance perfectly, that was at least possible. But there were precious few of those on Inferno, and with any other robot type the effort was pointless.

            Even so, the habit gave him a moment of time to consider the indirect meaning of the robot’s words. No “satisfactory interpretation of the evidence.” What the hell did that mean? Donald was trying to tell him something, something the robot did not choose to say directly, for fear of presuming too far. But Donald was never cryptic without a purpose. When Donald got that way, it was for a reason. Alvar Kresh was tempted to order Donald to explain precisely what he was suggesting, but he restrained his impatience.

            It might be better to see if he could spot the point that was bothering Donald himself, evaluate it independently without prejudgment. There was, of course, precious little a robot would miss that a human could notice. Much of what Donald had said was so much deferential nonsense, salve for the ego. But the words Donald had used were interesting: “The crime scene does not tell us much that we can use.” As if there were something there, but something distracting, meaningless, deceptive. So much for avoiding prejudgment, Alvar thought sardonically. That was the trouble with robot assistants as good as Donald--you tended to lean on them to much, let them influence your thinking, trust them to do too much of the background work. Hell, Donald could probably do this job better than me, Alvar thought.

            He shook his head angrily. No. Robots are the servants of humans, incapable of independent action. Alvar stepped through the doorway, fully into the room, and began to look around.

            Alvar Kresh felt a strange and familiar tingle course through him as he set to work. There was always something oddly thrilling about this moment, where the case was opened and the chase was on. A strange chase it was, one that started with Alvar not so much as knowing who it was that he pursued.

            And there was something stranger still, always, about standing in the middle of someone’ s very private space with that person absent. He had stood in the bedrooms and salons and spacecraft of the dead and the missing, read their diaries, traced their financial dealings, stumbled across the evidence of their secret vices and private pleasures, their grand crimes and tiny, pathetic secrets. He had come to know their lives and deaths from the clues they left behind, been made privy by the power of his office to the most intimate parts of their lives. Here and now, that began as well.

            Some work places were sterile, revealing nothing about their inhabitants. But this was not such a place. This room was a portrait of the person who worked here, if only Alvar could learn to read it.

            He began his examination of the laboratory. Superficially, at least, it was a standard enough setup. A room maybe twenty meters by ten. Inferno was not a crowded world by any means. People tended to spread out. By Inferno standards it was an average-sized space for one person.

            There were four doors in all, in the corners of the room, set into the long sides of the room: two on the exterior wall, leading directly to the outside, and two on the opposite, interior wall, leading into the building’ s hallway. Alvar noted that the room was windowless, and the doors were heavy; they appeared to be light-tight. Close them, cut the overhead lights, and the room would be pitch-black. Presumably they did some work with light-sensitive materials in here. Or perhaps they tested robot eyes. Would the reason for, or the fact of, a light-tight room be important or meaningless? No way to know.

            Alvar and Donald stood by one of the interior doors, toward what Alvar found himself thinking of as the rear of the room. But why is this end the rear? he wondered. No one specific thing, he decided. It was just that this end of the room seemed more disused. Everything was boxed up, in storage. The other end clearly was put to more active use.

            Work counters ran most of the length of the room, between the pairs of doors. There were computer terminals on the counters. The walls held outlets for various types of power supplies, and two or three hookups Kresh could not identify. Special-purpose datataps, perhaps.

            Every square centimeter of the countertops seemed to have something on it. A robot torso, a disembodied robot head, a stack of carefully sealed boxes, each neatly labeled Handle with Care. Gravitonic Brain. Alvar frowned and looked at the labels again. What the devil were gravitonic brains? For thousands of years, all robots had been built with positronic brains. It was the positronic brain that made robots possible. Gravitonic brains? Alvar knew nothing at all about them, but the name itself was unsettling. He did not approve of needless change.

            He filed away the puzzle for future reference and continued his survey of the room. All of the room’ s side counters were full of all sorts of mysterious-looking tools and machines and robot parts. Yet there was no feel of chaos or mess about the room; all was neat and orderly. There was not even so much as an air of clutter. It was merely that this entire room was in active use by someone who seemed to have several projects going at once.

            Two large worktables sat in the center of the room. A half -built robot and a bewildering collection of parts and tools were spread out on one table, while the other was largely empty, with just a few odds and ends here and there around the edges.

            Wheeled racks of test equipment stood here and there about the room. A huge contraption of tubing and swivels stood between the two tables. It was easily three meters tall, and took up maybe four meters by five in floor space. It was on power rollers, so it could be pushed out of the way when not in use.

            “What the devil is that thing?” Alvar asked, stepping toward the center of the room.

            “A robot service rack,” Donald replied, following behind. “It is designed to clamp onto a robot’s hard-attachment points and suspend the robot at any height and in any attitude, so as to position the needed part of the robot for convenient access. It is used for repairs or tests. I thought it a large and awkward thing to keep in the middle of the room. It would certainly interfere with easy movement between the two worktables, for example.”

            “That’ s what I was thinking. Look, you can see the empty space along the wall on the rear end of the room. They rolled it over there when they weren’t using it. So why is it out in the middle of the room? What good is an empty robot rack?”

            “The clear implication is that there was a robot in it recently,” Donald said.

            “Yes, I agree. And notice the empty space on the center of the empty worktable. About the right size for another robot there, too. Unless they moved the same robot from the table to the rack, or vice versa. Maybe that was the motive for the attack? The theft of one or two experimental robots? We’ll have to check on all that.”

            “Sir, if I could direct your attention to the floor in front of the service rack, Fredda Leving’s position on it has been marked out--”

            “Not yet, Donald. I’ll get there. I’ll get there.” Alvar was quite purposefully ignoring the pooled blood and the body outline in the center of the room. It was too easy to be distracted by the big, obvious clues at a crime scene. What could the body outline tell him? That a woman had been attacked here, bled here? He knew all that already. Better to work the rest of the room first.

            But one thing was bothering him. This room did not match Fredda Leving’s character. He knew her slightly, from the process of ordering Donald, and this place did not fit her. It had the feel of a male domain, somehow. Tiny details he had seen but not noted suddenly registered in Alvar’s consciousness. The size and cut of a lab coat hanging by the door, the size of the dust-sealed lab shoes sitting on the floor beneath the lab coat, certain tools stored on wall hooks that would be well out of reach for the average-sized woman.

            And there was, indefinably, something about the neatness of this room that spoke of a shy, compulsive, tidy man, something that did not match an assertive woman like Fredda Leving. If she lived up to her very public image, her lab would be a mess, even after the robots got through cleaning, for she would flatly refuse to let them near most of it. The great and famous Fredda Leving, hero of robotics research, the crown jewel of science in Inferno, was not a compulsive fussbudget--but the occupant of this room clearly was.

            Alvar Kresh stepped back into the hallway and checked the nameplate next to the door. Gubber Anshaw, Design and Testing Chief; it read. Well, that solved one minor mystery and replaced it with another. It wasn’t Leving’s lab, but Anshaw’s, whoever he was.

            But what was Fredda Leving doing in Anshaw‘s lab, presumably alone with her assailant, in the middle of the night?

            Kresh went back into the lab and walked around the rest of the room, careful not to touch anything, determined to resist the urge to go and look at the spot where the body fell. The room was a perfect forest of potential clues, jam-packed with gadgets and hardware that might have some bearing on the case, if only Alvar knew enough about experimental robotics. Was there indeed something missing, some object as big as an experimental robot, or as tiny as an advanced microcircuit, whose theft might provide a motive for this attack?

            But what was the nature of the attack? He knew nothing so far.

            At last, quite reluctantly, after working the rest of the crime scene and coming up with very little for his efforts, Alvar moved toward the center of the room, the center of the case, the scene of the attack.

            There it was, on the floor, between the two worktables, a meter or so in front of the large robot service rack. A pool of blood, a blotchy, irregular shape about a meter across. The body as found was indicated in a glowing yellow outline that followed the contours of the body perfectly, down to the sprawled-out fingers of the left hand. The fingers seemed to be reaching toward the door, reaching for help that did not come.

            Some errant part of Kresh’ s mind found itself wondering how they did that, how they put down that perfect outline. Robots in the Sheriff’s office knew how, but he did not.

            But no. It was tempting to distract himself with side issues, but he could not permit himself the luxury. He knelt down and looked at what he had come to see. He had forced himself not to notice the smell of drying blood until this moment, but now he had to pay attention, and the heavy, acrid, rotting odor seemed to surge into his lungs. A wave of nausea swept over him. He ignored the stench and went on with his grim task.

            The pool of blood was much smeared and splashed about by the med-robots, their footprints and other marks badly obscuring the story the floor had to tell. But that was all right. Donald would have images of the floor recorded straight off the med-robots’ eyes, what they saw the moment they came in. Computer tricks could erase all traces of the med-robots from whatever images the police observer/forensic robots had made, reconstruct the scene exactly as it was before. Some of his deputies only worked off such reconstructions, but Kresh preferred to work in the muddled-up, dirtied-up confused mess of the real-world crime scene.

            The blood had virtually all clotted or dried by now. Kresh pulled a stylus from his pocket and tested the surface. Almost completely solidified. It always amazed him how fast it happened. He looked up and from the pool of blood, noted the pattern of a med-robot’s foot and then noted something else he had seen before but merely filed away until he had seen the whole room. Two other sets of prints, clearly from robotic feet, but wholly different from the med-robot’s treads. One set of prints led out the front interior into the hallway, the other out the front exterior door to the outside of the building.

            And the two sets of prints might be different from the med-robot’s, but they were utterly identical to each other.

            Two sets of mystery prints, exactly like each other.

            “That’s what’s bothering you, isn’t it, Donald?” Alvar said, standing back up.

            “What is, sir?”

            “The robot footprints. The ones that make it clear that a robot--two robots--walked through the pool of blood and left Fredda Leving, quite possibly to die.”,

            “Yes, sir, that did bother me. The flaw is obvious, but it is what the evidence suggests.”

            “Then the evidence is wrong. The First Law makes it impossible for any robot to behave that way,” Alvar said.

            “And therefore,” a brash new voice suddenly declared from the door Alvar had come through, “therefore, someone must have staged the attack to make it seem like a robot--two robots--did it. Brilliant, Sheriff Kresh. That took me all of thirty seconds to figure out. How long have you been here?”

            Alvar turned around and clenched his teeth to keep from letting out a string of curses. It was Tonya Welton. A tall, dark-skinned woman, long-limbed and graceful, she stood just inside the doorway, a tall, dusky-yellow robot behind her. Alvar Kresh would not even have noticed the robot except that Welton was a Settler. He always got a certain grim pleasure out of seeing robots inflicted on the people who hated them so passionately, but at the moment at least, Welton seemed bothered not at all. Her expression was one of amused condescension.

            She was dressed in a disturbingly tight and extravagantly patterned blue one-piece bodysuit. The Spacer population on Inferno preferred much more modest clothing and far more subdued colors. On Inferno, robots were brightly colored, not people. But no one had told the leader of the Settlers on Inferno that--or else she had ignored them when they did tell her. Welton, more than likely, had gotten it backwards deliberately.

            But what the hell was Tonya Welton doing here now?

            “Good evening, Lady Tonya,” Donald said in his smoothest and most urbane tones. It was rare, surpassing rare, for a robot to speak except when spoken to, but Donald was smart enough to know this situation needed defusing. “What a pleasant surprise to have you join us here.”

            “I doubt it,” Tonya Welton said with a smile that Alvar scored as being at least an attempt at courtesy. “Forgive me, Sheriff Kresh, for my rather rude entrance. I’m afraid the news about Fredda Leving unsettled me. I tend to be a bit sharp-tongued when I am upset.”

            And at all other times, Kresh thought to himself. “Quite all right, Madame Welton,” he replied in a tone of voice that made it clear it was anything but all right. “I don’t know what business brings you here, but there has been an attack on one of Inferno’ s top scientists here tonight, and I cannot allow anything to interfere. This is an official investigation, Madame Welton, which has nothing to do with the Settlers, and I’m afraid I must ask you to leave.”

            “Oh, no, I can’t. You see, that’s why I’m here. Governor Grieg himself called me not an hour ago and asked that I come here tonight and join in your investigation.”

            Alvar Kresh stared at the Settler woman in openmouthed astonishment. What in the devil was going on here? “Are we done here, Donald?” he asked. “ Anything else I need to see immediately?”

            “No, sir, I think not.”

            “Very well, then, Donald. Seal this room as a crime scene. No one in or out. Just now, I think perhaps Madame Welton and I need to have a little talk, and this is not the place for it. Join us when you have completed the arrangements.”

            “Very good, sir,” Donald said.

            “Let’s go to my car, Madame Welton. We can talk there.”

            “Yes, let’s do that, Sheriff,” Tonya Welton said, rather stiffly. “There are a few things we need to get straight. Come along, Ariel.”

            ALVAR Kresh and Tonya Welton sat down in the Sheriff’s aircar, facing each other, both of them clearly wary. Welton’s robot, Ariel, stood behind her mistress, fading into the background as far as Kresh was concerned. Robots didn’t count.

            “All right, then,” he said. “What’s all this about? Why did the Governor call you in? What possible connection does this case have with the Settlers?”

            Tonya Welton folded her hands carefully and looked Kresh straight in the eye. “In a day or two you’ll get the answer to that. But for now, it’s classified.”

            “I see,” Kresh said, though he most certainly did not. “I’m afraid that is not much of an explanation.”

            “No, and I am sorry for that, but my hands are tied. There is, however, one thing I can tell you that will at least in part explain my being here. I do have authority to be here, under the agreement permitting a Settler presence on this world. I have the right to protect the safety of my employees.”

            “I beg your pardon?”

            “Oh, yes, didn’t you know?” Tonya Welton asked. “Fredda Leving is working for me.”

            There was a half minute’ s dead silence. Fredda Leving was famous, one of the top roboticists on the planet. Most Infernals regarded her not as a person, but as a planetary asset. For her and her labs to be reduced to mere employees of the Settlers--Welton might as well have announced that the Settlers had purchased Government Tower, or gotten title to the Great Bay.

            At last Alvar found his voice again. “If I could make a suggestion, Madame Welton, I think it might be wise to keep that fact very quiet indeed,” he said gruffly.

            Welton looked surprised. “Why? We haven’t publicized it widely, but we haven’t tried to keep it secret.”

            “Then I suggest you start,” Alvar said.

            “I’m afraid I don’t understand,” Welton said.

            “Then let me make this clear, Madame Welton. The average citizen of Inferno will not regard this attack as a mere assault, or as attempted murder. The citizens will see an attack on a top scientist, especially a roboticist, as sabotage. Many of them will simply assume your people did it, even without knowledge of Settler involvement in Leving Labs. Once they hear Settlers are involved, that will only make it worse.”

            “Our involvement!” Tonya Welton exclaimed. “We had nothing to do with the attack!”

            “That’s as may be,” Alvar said. Clearly Welton was upset, and he wanted her that way, wanted her off balance. What was she doing here, anyway? How had she gotten here so quickly? There was something damned suspicious in her haste and eagerness. Just what the hell kind of robotics work would the Settlers be interested in, anyway? There was more than one mystery in the air tonight.

            Donald slipped back into the aircar and took a place standing against the wall, next to Ariel. Kresh glanced at him and nodded. There was something comforting in having his loyal servant present. But Donald was not the issue here. Kresh took a good hard look at Welton, trying to gauge her mood. If he was any judge of such matters, there was an underlayer of uncertainty below all her brave talk. “You deny involvement,” he said, “but just now you spoke of Fredda Leving working for you. That is involvement enough. That alone will be seen as a threat by most of the people on this world.”

            “What in deep space are you talking about?” Welton demanded.

            “My fellow Infernals will see interference in robot research as an attack on the Spacers’ hopes of survival in a universe that seems to be surrendering itself to the Settlers. Given the slightest hint of any connection between the Settlers and the attack, however slender and tenuous, the people of this world will assume your people were behind it. They won’t care if it is true or not. They will believe.

            “They will associate this attack with the Settlers--the same damn Settlers they see wandering free allover Inferno, poking their noses into everything, treating the people of Inferno as little better than savages. It will be enough to make the situation even more tense than it is already. The people of Inferno are sure you Settlers regard us all as amusing little natives to be brushed aside on your way to conquering the galaxy.”

            Tonya colored a bit, and she folded her arms in front of her. “Politics. Always it comes down to politics and prejudice. My dear Sheriff. It is not we Settlers who are holding you Spacers back. You are doing it to yourselves, with no need of help from us. You have had endless generations in which to colonize new worlds of your own. You could have peopled thousands of worlds by now. Instead you have but fifty worlds--forty-nine after this Solaria business.

            “We did not stop you from going on to further colonization. You chose not to continue. Nor are we preventing you from starting a new effort at colonization now. But instead of taking action, you choose to remain at home and blame us for moving outward. Is it our fault that you have made your refusal to settle new worlds a mark of virtue?”

            “Madame Welton. You must excuse me,” Kresh said. “I allowed my own emotions to get the better of me. I did not intend to accuse you, but you are entitled to fair warning of what the people of Inferno will think if your--ah--involvement becomes known. I don’t hold such views myself, though I must admit some sympathy for them. But if a Settler relationship with Fredda Leving comes out in connection with this crime, or in any way at all, it is my considered professional opinion that there will be hell to pay.”

            Tonya Welton stared at him, unblinking, her face unreadable.

            At last she spoke. “Then I think you can look forward to having to pay that hell in about two days’ time,” she said, rather soberly.

            “What happens then?” he asked, his voice flat, his face deadpan.

            “There will be an--announcement,” she said, clearly being careful of what words she used. “I am not at liberty to say more, but if there are to be the sort of difficulties you are talking about, they will happen then.”

            “Beg pardon, Madame Welton, but do you think it possible that tonight’s attack has some connection to that announcement?” Donald asked. “Perhaps an attempt to stop or delay it?”

            Welton turned her head sharply toward Donald, her expression suddenly wild and uncontrolled. Obviously, she had not noticed him coming in. “Yes,” she said, a bit too eagerly. “Yes, I believe that is a real possibility. If it is true, then I believe we are all in terrible danger.”

            “What the devil are you--” Kresh began.

            “No,” Welton said, turning back toward Kresh. “I can say no more. But solve this case quickly, Sheriff. If there is anything in this life, this world, that you value, solve it!” She took a deep breath and seemed to come back to herself a bit. “It was a mistake for me to come here tonight,” she announced. She turned and looked about the aircar’s cabin, as if seeing it for the first time. “I will contact you tomorrow, Sheriff,” she said. “ And I will expect full and complete reports of your progress on a regular basis. Come, Ariel.”

            And without another word, she stepped out of the car, her robot following. Alvar Kresh watched them go, wondering just. what exactly Tonya Welton was up to. Her performance tonight was odd, to put it mildly. Putting aside the fact of her magically appearing almost before Kresh got to the crime scene, there was something else: the way she had latched on to the possibility of a political motive. It almost made Kresh think she wanted to draw attention toward that idea and away from something else. But what the hell could that something else be?

            All he knew for sure was that whatever was going on, he was already stuck, deep inside it.

CALIBAN walked the night, burning with curiosity. He was a great distance from his starting point, in a quiet residential area, the walkways all but completely deserted at this hour. The homes were large and widely scattered. Great lawns, some of them getting a bit dry, scruffy, and thin-looking, separated the houses. In this part of town, it seemed there was little ground traffic to speak of. Judging from the absence of a road wide enough for large vehicles, travel to and fro was by aircar or by foot.

            But a dying lawn was no less wondrous than a live one to Caliban. All the world was new to him, everything that he saw was a fresh and vibrant wonder. He saw the bright pinpoints of light in the sky and wondered what they were. He noticed a few bits of litter blown against a fence and wondered how such a strange combination of objects had come to be there. His datastore was mute on both of those subjects, and many others besides, but on the whole it was a splendid guide, telling him any number of things about the city through which he walked. He wandered everywhere, eagerly looking about at everything, marveling at all things. And if stars and litter were not explained, many other things were. More often than not, he could look at a thing, and wonder about it, and find that the datastore could identify it and explain it for him.

            He was content for some time to wander the city, passively absorbing whatever the datastore saw fit to tell him about what he saw. Then Caliban had an idea. If the map and the datastore could work to tell him about what was before him, could they not also guide his steps? Perhaps he could examine the datastore ‘ s map, select an interesting destination, and travel to it.

            He stopped in his tracks and tried the experiment. The outside world seemed to fade from his sight. Suddenly he was looking down on a map-schematic of the area he was in, done in bold primary colors and carefully designed symbols.

            He tried to push outward from that point and was greatly pleased to discover that the simple act of wishing it to be so allowed him to visualize the entire city map, or focus in on any portion of it. Nor, he found, did his virtual viewpoint have to stay above the map. He could move down to ground level and see the buildings and hill tower over him. He could visualize the map data from any angle or position.

            A few moments of experimentation confirmed it: He could manipulate his viewpoint to any spot in or over the map, look at the lay of the land from a bird’s-eye view, or from ground level at any position, with the buildings and streets presented in the proper shapes and sizes. His vision swept along great swatches of the city, across the parks, the buildings, the great roads. It was as if he were traveling through those places in his mind. The sensation was exhilarating, almost one of flight.

            There were datatags on the map, offering information on the buildings--their names and addresses, and in many cases the names of whatever businesses went on there.

            Suddenly he got a splendid idea. He could use the datatag information to learn more about himself. He manipulated his viewpoint within the map and brought it back to his present position. Then he proceeded to retrace his steps back to the building he had started out from. He could read the datatags connected to the building and learn what sort of place it was, see what other information the map held concerning it. Certainly he could find clues to his own identity, his place in the world. Eager to find out more about himself, he moved his viewpoint rapidly across the map, back the way he had come.

            The map imagery rushed past him at a breakneck pace, twisting and turning violently, reversing his movements at tremendous speed. At last the images came back to his starting place. He made a strange discovery: The image of the building was incomplete. Nearly every other building was shown in great detail, with doors and windows and basic elements of the architecture clearly shown. But the map showed this building as nothing but a featureless grey rectangular solid, a low, long shape on the land.

            Confused, Caliban accessed the datatag system.

            And discovered that the map had no information whatsoever about the building inside which he had awakened.

            Stunned, surprised, Caliban shut down the map display system. The bright colors and symbols of the map faded from his vision, and he found himself once again standing in the darkness, alone on an empty pathway in a quiet residential district.

            Why was there no information about that building? Perhaps he should go back there, examine the place firsthand. He of course had a perfect, detailed memory of what he had seen there, and no doubt he could work his way back through those memories for information. But he had not been looking for anything when he awakened, had not even been fully aware that he should have known more than he did. If he went back, he would learn more.

            He turned around, was about to head back the way he had come, toward the lab. But then he stopped. Wait a moment. There was another factor. One he had not considered yet. He recalled that first moment of awakening, the sight of the woman unconscious at his feet, the blood pooling about her head. The cross-index system of his datastore flitted through a whole series of things even as he thought about that moment.

            And it settled at a quotation from the Legal Code that leaving the scene of a crime before being interviewed by the police was itself a crime. His mind flittered through all the datastore had to say about the Legal Code, the concept of crime, and the idea of punishment and rehabilitation. All of it seemed to relate to humans, but it was not a great leap of reasoning to assume that committing a criminal act could mean trouble for a robot as well.

            No, he could not go back there.

            Wait a moment. Were there other blanks on the map? Other places where detail was limited in some way? Perhaps other places with limited information on the datastore would have something in common with the building he had left. Perhaps examining one of them would offer some clue; perhaps some thought or image would stimulate the datastore to offer some sort of information that could tell him about himself.

            Caliban looked about the area and decided it would be best to get off the pathway while he was examining the map. He stepped off the path and walked a short way, until he found a slight depression in the rolling landscape. He sat down in it, reasonably sure he could not be seen from the path.

            He returned his attention to the datastore map. At first, his mind cast back and forth across the map in random, swooping passes, trying to cover as much ground as quickly as possible while still keeping track of any building or place that seemed suspiciously blank. Then he resolved to quarter the whole city and go block by block, in an orderly manner. Perhaps there was something he could learn from the pattern of blanked places, something he could discern only when he had located them all.

            The map of the city had definite edges to it, precise boundaries beyond which was nothingness. Caliban’s knowledge of the world, the universe, stopped at those borders. For a moment, Caliban toyed with the idea of venturing to the closest of those boundaries, just to see what it was like. He imagined himself standing on the edge of the world, looking down into nothingness. The idea was exciting and disturbing.

            But no. It would not do to get sidetracked. First he must get answers about himself and about what had happened at the building where he had awakened. After those two mysteries were resolved, he could take the time to indulge his idle curiosity.

            He set to work at the southern edge of the map and began to work across it methodically, examining a strip from east to west, then moving northward to examine the next strip, west to east.

            And then he found it. Not far from the southern edge of the map was a great void, an emptiness a thousand times, ten thousand times larger than the blank, unmarked building in which he had awakened. But this was no area without detailed markings. This was emptiness, the absence of all things. No land, no water, no buildings, no roads. There was nothing there at all.

            He wondered if the map was reporting literal truth. What could such a void look like in real life? What would cause it? His curiosity, his eagerness to see this place, was all but uncontrollable. But he held firm to his plan. He must examine the whole city, absorb the whole of the datastore map into his active memory. There could be other voids as well, equally significant. He held to his search pattern, moving south to north, shuttling east to west, west to east.

            It took the better part of an hour, but at last Caliban had worked his way across the whole of the map of Hades. Yes, there were other voids, but none of them were even a fraction as large as the first he had found. Yes, there were other unmarked, unlabeled buildings, but he could not see any obvious pattern, no relation to the features on the rest of the map, that told him anything meaningful, or anything at all.

            There was nothing left for it but to go and look. Now there was no reason to resist the temptation to see what the great void looked like. Caliban stood up and walked back to the field, using his infrared vision to move easily through the darkness.

            The site of the void was a good distance across the city, and the first hints of dawn were lighting the east as he traveled through the semi-arid, half-populated expanses of Hades, imagining what a great emptiness would look like.

            But what he saw when he got there was no blank on the map. As the dawn broke full over the horizon, Caliban stood at the edge of where the map said there was only emptiness.

            What Caliban saw was a lively oasis in the midst of the fading city. He stood at the edge of a broad and verdant park, dotted stands of trees, great lawns, spraying fountains.

            Small pavilions dotted the landscape and seemed to give access to underground facilities, judging by the people going in and out. Caliban walked along the low stone wall that formed the perimeter of the park, until he came to the entrance.

            Settlertown, a sign said. Caliban stared at it in confusion. Another mystery. He had no idea what Settlers were, or why they should have their own town. He called to the datastore, but it had no information on any such term.

            For some reason, all information regarding both his origin point and this place had been deleted from his datastore.

            But why would anyone do that?

            DARKNESS had passed, and dawn had come over the horizon, and the morning was well begun. Alvar Kresh paced the room, listening to the routine words of the routine interrogation of yet another routine coworker, one Jomaine Terach. Terach wasn’t normally up and at the lab by this hour, but he lived quite near the lab and all the commotion had wakened him. He had wandered over to see what was going on--or so he claimed. Police officers throughout history had been a little slow to believe witnesses who explained trifles such as coming to work with such elaboration--and Kresh was tempted to uphold that tradition in the present instance. It would be wise to treat everyone as a suspect just at the moment.

            Kresh let Donald do most of the work. This night had been a long, hard journey through the darkness to the day. Crime scenes could be grueling.

            They had taken over the duty office for the purpose of doing the intake interrogations, taking each worker as he or she arrived. The duty office was designed to accommodate an overnight stay, in case an experiment ran all night. The office featured a large and rather comfortable-looking bed, much better than the miserable cot in the duty room at Sheriff’s HQ. After a sleepless night, it looked more than slightly inviting.

            “Tonya Welton claims that Fredda Leving was--is--working ; for her. Is that true?” Donald asked.

            “Absolutely not,” Jomaine Terach said, yawning mightily. “Fredda Leving has never worked for anyone but herself in her life, and she isn’t likely to start in by oiling up to the high and mighty Queen of the Settlers.” He yawned again. “My God, it’s early. Have you been at it since the attack?”

            “Yes, sir. We have been here working straight through the night,” Donald said.

            “So she and Tonya Welton don’t get along,” Kresh said, brushing aside Terach’s and Donald’s pleasantries. He sat back down at the table, next to Donald and opposite Terach. He drummed his fingers on the desktop, trying to keep his exhausted mind from wandering. Maybe he should have gone home instead of staying here all night.

            Now, where was he? Damn it, his mind was wandering. He was getting fuzzy. He wasn’t going to learn much of anything if he was too exhausted to think. “So they didn’t like each other,” he said again, trying to cover up his overlong pause. “Were they at least polite around each other?”

            “No, sir, not in the least,” Jomaine said. “Not anymore. They used to be much closer, real friends, I thought. Now there isn’t much left but the professional relationship.”

            That was an interesting tidbit. Tonya Welton and Fredda Leving, each with a real reputation for being a hard-edged infighter. He could easily imagine them coming to a parting of the ways. It was far harder to imagine them becoming friends in the first place.

            But being personally involved with the victim made it just that much more peculiar that Welton would barge into the investigation. She must have known that Kresh would quickly learn about the friction between herself and the victim. It was very early in the going, but right now, she was the one with the best motive for the attack. Why draw attention to herself?

            Alvar Kresh leaned back in his chair and looked across the desk at the man he was interviewing. Jomaine Terach was a tall, thin man, sandy-haired, pale, with a long, thin face and a sharp-pointed nose. There was something a bit overrefined, overformal, about his manner of speech.

            Kresh repressed a yawn. It hardly seemed worth staying up all night just to listen to the likes of Terach.

            Alvar rubbed his eyes and brought his mind back to where he was in the questioning.” I find it hard to imagine the two of them as friends. Settlers hate robots, and Leving was one of the leading proponents of more and better robots. I can’t see how much they would have in common,” Kresh said.

            “I think perhaps that was part of what made the friendship work--at least for a while. They enjoyed debating each other. But then things fell apart between them. Maybe it just got a little too intense,” Terach suggested.

            “But if she wasn’t Tonya Welton’s employee, Master Terach, and they were no longer friends,” Donald 111 said, “might one ask what their relationship was?”

            Terach glared at Donald. It clearly annoyed him to be questioned by a robot. But he was smart enough not to protest out loud.

            Kresh watched Terach with a detached, professional interest. He often ordered Donald to take an active part in the questioning. It was a variation on the ancient good-cop, bad-cop routine. Donald unsettled the interrogation subjects, and then the subjects answered Kresh, looking to him for support and understanding, unwisely trusting him over Donald.

            “They were collaborators, I suppose.” Terach turned toward Kresh. “There’s a lot I can’t say about the work at the lab,” he apologized.

            “I’ve heard that more than once,” Kresh growled. “Every employee I’ve talked to has told me that. Those seem to be the only words most of your people know.”

            “I’m sorry about that.”

            “Don’t be. We’ll be back once I’ve gotten the Governor to grant me some clearances.”

            That prospect didn’t seem to please the rather reedy-looking Jomaine Terach. “Well, perhaps you needn’t bother, once the public announcement is made.”

            “And I’ve heard that, too, and I know bloody damn well you’re about to tell me you can’t say anything more,” Kresh said. “So let’s talk about something else. Tell me why Fredda Leving would be in Gubber Anshaw’s lab in the middle of the night.”

            Terach seemed genuinely astonished. “Oh, my heavens, I wouldn’t attach any great importance to that,” he said. “We’re in and out of each other’s labs all the time. The work is of a highly--ah--collaborative nature, and I expect that she was simply working on some subcomponent that happened to be in his lab.”

            “Infernals tend to be rather territorial people,” Kresh suggested. “We like to have our own space.”

            Terach shrugged. “That may be so, but that doesn’t mean everyone is compulsive about it,” he said, a bit pointedly.

            “Mmmph,” Kresh grunted, not altogether convinced, and ignoring the gibe that was clearly intended to distract him. “Well, then, maybe you can tell me where the devil Gubber Anshaw is. He hasn’t shown up this morning and we have not been able to reach him at home. We assume he’s there, but his robots flatly refuse to confirm that, or to pass on any messages.”

            “I’m not surprised,” Jomaine said. “Gubber likes to work at home, in complete privacy. He’s taken to doing it more and more recently. Sometimes we kid him that if you police threw an arrest perimeter around his house, he wouldn’t even notice.”

            Kresh grunted noncommittally. Privacy, and the sanctity of the home, were indeed highly valued commodities on Inferno. Indeed, it was illegal to arrest a person in his or her home. The law was very precise on that point, and on the procedures that could and could not be followed. The police and their robots could wait outside until hell froze over, they could search the premises once an arrest was made, but they could not enter the home to effect the arrest.

            It had happened more than once that a suspect had refused to come out for a long period of time. Precedents and rules of procedure had long ago been established in such cases, setting out what could and could not be done. The police could cut off all communications links to the surrounded house, but not food, or water, or power. Sometimes the prohibition against home arrests actually worked to police advantage: If kept up long enough, the police-robot vigil outside a suspect’s home amounted to house arrest without all the bother and expense of a trial.

            “Well, it might come to an arrest perimeter if we don’t hear from him soon,” Kresh said warningly. “You might get that information to him.”

            Jomaine cocked a surprised eyebrow at Kresh. “Have a little patience, Sheriff. Gubber rarely comes in much before midday on the days he does come in,” he said. “He spends his mornings at his home, working on other research projects. Most days--but not all of them--he comes in here and works on Leving Lab projects about midday and through the evening. But as I said, he doesn’t always come in. He’s not held to any sort of schedule.”

            Jomaine thought for a moment. “Come to think of it, I don’t recall seeing him when I came through here last night. I doubt he was here. My guess is he’s been at home, working, the entire time, quite unaware that anything has happened. And yes, his robots have strict orders to prevent his being disturbed. But that is routine with him. I wouldn’t suggest that you read anything into his absence, or waste any time thinking he had something to do with the attack on Fredda.”

            Alvar Kresh frowned. “Why not? It was his lab she was attacked in. At this point we have no suspects, no motive, no real information at all. I don’t know Gubber Anshaw or anything about him. I see no reason to eliminate anyone at this point, especially someone who would seem to have the opportunity to commit the crime. Coworkers have been known to have motives for murder.”

            “Well, there’s your argument against suspecting him right there,” Jomaine said, a bit overeagerly. “Gubber Anshaw had no motive for attacking Fredda, and every reason for wishing her well. I suppose, yes, he might have had the means and the opportunity to assault her--but Sheriff Kresh, you have the means and the opportunity to pull your blaster from your holster right now and vaporize my head. That doesn’t mean you will do it. You have no motives for killing me--and a lot of motives for not hurting me. You ‘ d lose your job and get thrown in jail, at the very least. But it goes past that. Fredda was a great help to Gubber. He would most definitely not want to lose that.”

            “You are suggesting that Gubber Anshaw would have a great deal to lose if something happened to Fredda Leving?” Donald asked.

            Jomaine Terach looked cautiously at Donald, and then at Kresh. “Once again, that gets us into classified areas. But yes, I think that would be safe to say. Gubber had made some remarkable advances, advances that required the rejection of some very tried and true technology in favor of something newer and better and more flexible. However, he didn’t get far in promoting his discoveries. Robotics is in many ways a very conservative field. Leving Labs was the only place that was willing to use his work.”

            “I suppose we’re talking about gravitonic brains here,” Kresh said.

            Terach breathed in sharply, clearly surprised and unsettled. “How did you--”

            “There was a stack of them in neatly labeled boxes in Anshaw ‘ s lab,” Kresh said, more than a bit sardonically. “I think perhaps you need to work a little on security procedures down at the lab.”

            “Apparently so,” Terach said, clearly nonplussed.

            “So what the devil are gravitonic brains? Some sort of replacement for the positronic brain?”

            Donald turned his head toward Kresh. “Sir! That would be quite impossible. The positronic brain is the basis, the core, of all robotics. The Three Laws are intrinsic to it, built into its very structure, burned into its fundamental pathways.”

            “Take it easy, Donald,” Kresh said. “That doesn’t mean that the Three Laws couldn’t be built into another form of brain. Right, Terach?”

            Terach blinked and nodded, still a bit distracted. “Of course, of course. I really cannot say anything specific about gravitonic brains, but I suppose it can’t do any harm to speak in broad generalities. Gubber Anshaw is really just at the beginning of his research on gravitonics, but in my opinion he’ s already made tremendous breakthroughs. It’s time someone did.”

            “How do you mean?”

            “I mean that we have rung out the changes on positronics. Certainly today’s positronic brain is far superior to the original units. It has been greatly advanced and improved. There have been many refinements in it. But the positronic brain’s basic design hasn’t changed in thousands of years. It would be as. if we were still using chemical rockets for spacecraft, instead of hyperdrive. The positronic brain is an incredibly conservative design that puts tremendous and needless limits on what robots can do. Because the Three Laws are embedded in its design, the positronic brain is seen as the only possible design for use in robots. That is an article of belief, of faith, even among robotics researchers. But gravitonics could change all that.

            “Gravitonic brains currently have one or two minor drawbacks, but they are at the beginning of their development. They promise tremendous advantages over positronics, in terms of flexibility and capacity.”

            “Well, you certainly sound like a true believer yourself,” Kresh said dryly. There is none so faithful as the converted, he thought. “Very well, Terach. I may well wish to talk with you later, but that will do it for now. You may go.”

            Jomaine nodded and stood up. He hesitated before heading for the door. “ Ah, one question,” he said. “What is the prognosis for Fredda Leving?”

            Kresh’s face hardened. “She’s still unconscious,” he said, “but they expect her to awaken sometime in the next day or so, and go on to a rapid and complete recovery. They are using the most advanced regeneration techniques to stimulate recovery. I understand her head injury should be completely healed within two days.”

            Jomaine Terach smiled and nodded. “That’s excellent news,” he said. “The staff here will be delighted to hear it--ah, that is, if I’m allowed to tell them.”

            Kresh waved his hand in negligent dismissal. “Go right ahead, Terach. It’s public knowledge--and she’s under heavy guard.”

            Terach pasted on a patently false smile, nodded nervously, and left the room.

            Kresh watched him go. “What’s your reading, Donald?” he asked, without looking over at the robot. No one talked about it much, but advanced police robots were specially engineered to detect the body’ s involuntary responses to questions. In effect, Donald was a highly sophisticated lie detector.

            “I should remind you that Jomaine Terach quite possibly knows about my capabilities as a truth-sensor. I have never met him before, but a records-check confirms that he was on staff here during my construction. That does add a variable. However, suffice to say that he was highly agitated, sir. Far more so than any of the others, and, in my opinion, more so than would be accounted for solely by surprise and concern over the attack on Lady Leving. Voice stress and other indicators confirm that he was concealing something.”

            That didn’t surprise Alvar. All witnesses concealed things. “Was he lying?” he asked. “Lying directly?”

            “No, sir. But he was most concerned to learn we knew about the gravitonic brains. I found this confusing, as he went to some length to discuss them. I formed the impression that he was intent on steering the interrogation away from some other point.”

            “You caught that, too, I see. The damnable thing is that I can’t imagine what point he was trying to lead us away from. My hunch is he thinks we know more than we do.”

            “That is my opinion as well.”

            Alvar Kresh drummed his fingers on the table and stared at the door Jomaine Terach had used to leave the room.

            There was more going on here than the attack on Leving. Something else was up. Something that involved the Governor, and Leving, and Welton, and the Settler-Spacer relationship on Inferno,

            Indeed, the attack was already beginning to recede in importance in his mind. That was merely the loose thread he was tugging on. He knew that if he left it alone, the rest of it would never be revealed. Pull it too hard, and it would snap, break its connections to the rest of the mystery. But play the investigation of the attack carefully, tug the thread gently, and maybe he could use it to unravel the whole tangled problem.

            Alvar Kresh was determined to find out all he could.

            Because something big was going on.

            JOMAINE Terach left the interview room. His personal robot, Bertran, was waiting outside in the hall and dutifully followed him as Jomaine hurried back to his own laboratory.

            Sheriff Kresh had made Bertran wait outside the room during the interrogation. It was just a little harassment, Jomaine told himself, another way for Kresh to get and keep me unnerved. And yes, he admitted to himself, it had worked. Spacers in general, and Infernals particularly, did not like to be without their robots.

            Only after he was in his own lab, only after Bertran had followed him in and shut the door safely behind him, did Jomaine allow himself to succumb to the fears he was feeling. He crossed the room hurriedly. He dropped back into his favorite old armchair and breathed a sigh of relief.

            “Sir, are you all right?” Bertran asked. “I fear the bad news about Lady Leving and the police interview have greatly distressed you.”

            Jomaine Terach nodded tiredly. “That they have, Bertran. That they have. But I’ll be fine in just a moment. I just need to think for a bit. Why don’t you bring me some water and then retire to your niche for a while?”

            “Very good, sir.” The robot stepped to the lab sink, filled a glass, and brought it back. Jomaine watched as Bertran went over to his wall niche and dropped back into standby mode.

            That was the way it was supposed to be. A robot did what you told it to do and then got out of the way. That was how it had been for thousands of years. Did they really dare try and change that? Did Fredda Leving truly think she could overturn everything that completely?

            And did she truly have to make a deal with the devil, with Tonya Welton, in order to make it happen?

            Well, at any rate, he had managed to steer things away from any discussion of the Three Laws. If he had been forced to sacrifice a few tidbits about gravitonics in order to accomplish that, so be it. It would all be public in a day or so, anyway.

            They were safe for the moment. But still, the project was madness. Caliban was madness. Building him had been a violation of the most basic Spacer law and philosophy, but Fredda Leving had gone ahead, anyway. Typical bullheadedness.

            Never mind theory and philosophy, she had said. They were an experimental lab, not a theory shop that never acted on its ideas. It was time to take the next step, she said. It was time to build a gravitonic robot with no limits on its mind whatsoever. A blank slate, that’s what she had called Caliban. An experimental robot, to be kept inside the lab at all times, never to leave. A robot with no knowledge of other robots, or the Settlers, or anything beyond human behavior and a carefully edited source of knowledge about the outside world. Then let it live at the lab, under controlled conditions, and see what happens. See what rules it developed for its own behavior.

            Did she truly have to build Caliban?

            No, ask the question directly, he told himself. We’ve all hedged around it long enough. And yes, that was the deadly secret question. No one else knew. With Caliban broken free of the lab, with Fredda unconscious, there was no one else in the wide world who could ask the question.

            So Jomaine asked it of himself.

            Did she really have to build a robot that did not have the Three Laws?

SIMCOR Beddle lifted his left hand, tilted his index finger just so, and Sanlacor 123 pulled back his chair with perfect timing, getting it out from behind him just as Simcor was getting up, so that the chair never came in contact with Simcor’s body as he rose.

            There was quite a fashion for using detailed hand signals to command robots, and Simcor was a skilled practitioner of the art.

            Simcor turned and walked away from the breakfast table, toward the closed door to the main gallery, Sanlacor hard on his heels. The door swung open just as he arrived at it. The Daabor unit on the other side of the door had no other job in the world but to open it. The machine marked out its existence by standing there, watching for anyone who might approach from its side of the door, and listening for footsteps from inside the room.

            But Simcor Beddle, leader of the Ironheads, had no time to think about how menial robots spent their days. He was a busy man.

            He had a riot to plan.

            Simcor Beddle was a small, rotund man, with a round sallow face and hard, gimlet eyes of indeterminate color. His hair was glossy black, and just barely long enough to lie flat. He was heavy-set, there was no doubt about that. But there was nothing soft about him. He was a hard, determined man, dressed in a rather severe military-style uniform.

            Managing his forces, that was the main thing. Keeping them from getting out of control was always a problem. His Ironheads were a highly effective team of rowdies, but they were rowdies all the same--and as such, they easily grew restive and bored. It was necessary to keep them busy, active, if he were to keep them under any sort of control at all.

            No one quite knew where the Ironheads had gotten their name, but no one could deny it was appropriate. They were stubborn, pugnacious, bashing whatever was in their way whenever they saw fit. Maybe it was that stubbornness that earned them their name. More likely, though, it was their fanatical defense of the real Ironheads--robots. Well, granted, no one used anything as crude as raw iron to make robot bodies, but robots were as hard, as strong, as powerful, as iron.

            Not that the Ironheads held robots themselves in any special esteem. If anything, Ironheads were harder on their robots than the average Infernal. But that was not the point. Robots gave humans such freedom, such power, such comfort. Those things were the birthright of every Infernal, indeed of all Spacers, and the Ironhead movement was determined to preserve and expand that birthright by any means necessary.

            And making life unpleasant for the Settlers certainly fit into that category.

            Simcor smiled to himself. That was getting to be a bad habit, thinking in speeches like that. He crossed to the far side of the gallery, toward his office, and another door robot swung the door wide as he approached. He entered the room, quite unaware of Sanlacor moving ahead of him to pullout his chair from his desk for him.

            But he did not sit down. Instead, he made a subtle gesture with his right hand. The room robot, Brenabar, was at his side instantly, bringing Simcor’s tea. He took the cup and saucer and sipped thoughtfully for a moment. He nodded his head a precise five degrees down toward the desktop, and spoke one word. “Settlertown.”

            Sanlacor, anticipating his master, was already at the view controls, and in less than a second, the bare desktop was transformed into a detailed map of Settlertown. Simcor handed his teacup to the empty air without looking, and Brenabar took it from him smoothly.

            Kresh’ s deputies were sure to be ready for them, after last night. Simcor had superb connections inside the Sheriff’s Department, and he knew everything Kresh knew about the attack on Fredda Leving. In fact, he knew quite a bit more. He had heard a recording of that lecture of hers. Damnable, treasonous stuff. Simcor smiled. Not that she was likely to make any more such speeches. Everything was working his way.

            But he had to concentrate on the plans for today. He had to assume the Sheriff’s Department was ready for trouble. Once the Ironheads started the ruckus, they would only have a few minutes before the law stepped in to protect the damned Settlers.

            So they would have to do as much damage as possible in those first few minutes. Under the circumstances, it was too much to hope they would be able to penetrate the underground section of Settlertown again. No sense wasting effort in the attempt. This time, it would have to be on the surface, at ground level. Simcor Beddle lay his hands on the desktop and stared thoughtfully at the map of his enemy’s stronghold.

            IT was morning in the city of Hades. Caliban knew that much for certain, if very little else of any substance. By now he was no longer sure what he knew.

            But he was beginning to believe something was wrong. Something was terribly wrong.

            It was as if Caliban’s utterly blank memory and the precise but limited information in the datastore were the double lenses of a distorted telescope, utter ignorance and expert knowledge combining to twist and warp all he saw. The world his eyes and mind presented to him was a crazed and frightening patchwork.

            In the busiest part of the city’s midtown, he turned off the sidewalk and found a bench set in a quiet corner of a tiny park, well out of sight from any casual passersby. He sat down and began reviewing all that he had seen as he had walked the streets of Hades.

            There was something distinctly unreal, and somewhat alarming, about the world around him. He had come to realize just how clean, perfect, idealized, precise were the facts and figures, maps, diagrams, and images that leapt up from the datastore. But the real-world objects that corresponded to the datastore’s concepts were far less precise.

            Further exploration confirmed that false voids and featureless buildings were not the only flaws in the datastore map.

            The map likewise did not report which blocks were busy, full of people and robots, and which were empty, semi-abandoned, even starting to decay.

            Some new buildings had materialized since the map was stored in his datastore, and other, older buildings that seemed whole and complete in the datastore had vanished from reality.

            No image in the datastore showed anything to be worn-out or dirty, but the real world was full of dust and dirt, no matter how vigorously the maintenance robots worked to keep it all clean.

            Caliban found the differences between idealized definitions and real-world imperfections deeply disturbing. The world he could see and touch seemed, somehow, less real than the idealized, hygienic facts and images stored deep inside his brain.

            But it was more than buildings and the map, or even the datastore, that confused him.

            It was human behavior he found most bewildering. When Caliban first approached a busy intersection, the datastore showed him a diagram of the correct procedure for crossing a street safely. But human pedestrians seemed to ignore all such rules, and common sense, for that matter. They walked wherever they pleased, leaving to the robots driving the groundcars to get out of the way.

            Something else about the datastore was strange, even disturbing: There was a flavor of something close to emotion about much of its data. It was as if the opinions, the feelings, of whoever implanted the information into the datastore had been stored there as well.

            He was growing to understand the datastore on something deeper than an intellectual level. He was learning the feel of it, gaining a sense of how it worked, developing reflexes to help him use it in a more controlled and useful manner, keep it from spewing out knowledge he did not need. Humans had to learn to walk: That was one of many strange and needless facts the datastore had provided. Caliban was coming to realize that he had to learn how to know, and remember.

            Confusion, muddle, dirt, inaccurate and useless information--those he could perhaps learn to accept. But it was far more troubling that, on many subjects, the datastore was utterly--and deliberately--silent. Information he most urgently wanted was not only missing but excised, purposely removed. There was a distinct sensation of emptiness, of loss, that came to him when he reached for data that should have been there and it was not. There were carved-out voids inside the datastore.

            There was much he desperately wanted to know, but there was one thing in particular, one thing that the store did not tell him, one thing that he most wanted to know: Why didn’t it tell him more? He knew it should have been able to do so. Why was all information on that place where the sign said Settlertown deleted from the map? Why had all meaningful references to robots been deleted? There was the greatest mystery. He was one, and yet he scarcely knew what one was. Why was the datastore silent on that of all subjects?

            Humans he knew about. At his first sight of that woman he saw when he awoke, he had immediately known what a human was, the basics of their biology and culture. Later, when he glanced at an old man, or one of the rare children walking the street, he knew all basic generalities concerning those classes of person--their likely range of temperament, how it was best to address them, what they were and were not likely to do. A child might run and laugh, and adult was likely to walk more sedately, an elder might choose to move more slowly still.

            But when he looked at another robot, one of his fellow beings, his datastore literally drew a blank. There was simply no information in his mind.

            All he knew about robots came from his own observation. Yet his observations had afforded him little more than confusion.

            The robots he saw--and he himself--appeared to be a cross between human and machine. That left any number of questions unclear. Were robots born and raised like humans? Were they instead manufactured, like all the other machines that received detailed discussion in the datastore? What was the place of the robot in the world? He knew the rights and privileges of humans--except as they pertained to robots--but he knew nothing at all of how robots fit in..

            Yes, he could see what went on around him. But what he saw when he looked was disturbing, and baffling. Robots were everywhere--and everywhere, in every way, robots were subservient. They fetched and they carried, they walked behind the humans. They carried the humans’ loads, opened their doors, drove their cars. It was patently clear from every scrap of human and robot behavior that this was the accepted order of things. No one questioned it.

            Except himself, of course.

            Who was he? What was he? What was he doing here? What did it all mean?

            He stood up and started walking again, not with any real aim in mind, but more because he could not bear to sit idle any longer. The need to know, to understand who and what he was, was getting stronger all the time. There was always the chance that the answer, the solution, was just around the corner, waiting to be discovered.

            He left the park and turned left, heading down the broad walkways of downtown.

            HOURS went by, and still Caliban walked the streets, still deeply confused, uncertain what he was searching for. Anything could contain the clue, the answer, the explanation. A word from a passing human, a sign on a wall, the design of a building, might just stimulate his datastore to provide him with the answers he needed.

            He stopped at a corner and looked across the street to the building opposite. Well, the sight of this particular building did not cause any torrent of facts to burst forth, but it was a strange-looking thing nonetheless, even considering the jarringly different architectural styles he had seen in the city. It was a muddle of domes, columns, arches, and cubes. Caliban could fathom no purpose whatsoever in it all.

            “Out of my way, robot,” an imperious voice called out behind him. Caliban, lost in his consideration of things architectural, did not really register the voice. Suddenly a walking stick whacked down on his left shoulder.

            Caliban spun around in astonishment to confront his attacker.

            Incredible. Simply incredible. It was a tiny woman, slender, thin-boned, easily a full meter shorter than Caliban, clearly weaker and far more frail than he was. And yet she had deliberately and fearlessly ordered him about,’ instead of merely stepping around him, and then struck at him--using a weapon that could not possibly harm him. Why did she not fear him? Why did she have such obvious confidence that he would not respond by attacking her, when he could clearly do so quite effectively?

            He stared at the woman for an infinite moment, too baffled to know what to do.

            “Out of my way, robot! Are your ears shorting out?”

            Caliban noticed a crowd of people and robots starting to form around him, one or two of the humans already betraying expressions of curiosity. It would clearly be less than prudent to remain here, or attempt to respond when he so clearly did not understand. He stepped aside for the lady and then picked a direction, any direction but the one she had taken, and started walking again. Enough of aimless wandering. He needed a plan. He needed knowledge.

            And he needed safety. Clearly he did not know how to act like a robot. And the expressions, some of them hostile, he had seen on the faces of the passersby told him it was dangerous to be peculiar in any way.

            No. He had to lie low, stay in the background. Safer to blend in, to pretend to be like the others.

            Very well, then. He would blend in. He would observe the behavior he saw around himself, work determinedly to get lost among the endless sea of robots around him.

            KRESH walked the streets of Hades at the same hour, though with more certain purpose. He found that it helped to clear his head and refocus his attention if he got away from his office, got away from the interrogation rooms and evidence labs, and stretched his legs under the dark blue skies of Inferno. There was a cool, dry wind blowing in from the western desert, and he found that it lifted his spirits. Donald 111 walked alongside him, the robot’ s shorter legs moving almost at double time in order to keep up with Alvar.

            “Talk to me, Donald. Give me an evidence summary.”

            “Yes, sir. Several new facts have come to light from the hospital and our forensic lab. First and foremost, we have confirmed that the bloody footprints match the tread patterns of a standardized robot body model manufactured at Leving Labs. That robot body is a large general-purpose model, used with various brain types and body modifications for various purposes. The length of the footprints’ stride precisely matches that of the standard specification for that robot body model. The wound on Fredda Leving, s head corresponds to the shape and size of the arm of the same robot type, striking from the rear and to the left of the victim, from an angle consistent with Fredda Leving, s height and the height of that robot model--though all of those measurements are approximate, and any number of other blunt instruments would match, and a whole range of heights, forces, and angles would also be consistent with the wound.

            “Microtraces of a red paint found in Madame Leving’ s scalp wound likewise correspond to a paint used on some robots at Leving Labs, though it has not been definitively established that the paint in question was used on the robot model in question. I might add that it could not be immediately established whether the microtraces were from fresh or fully dried and hardened paint, as it was some hours before the labtech robots secured the samples. Further tests should answer that question.”

            “So the only suspect we are offered is a robot. That’s impossible, of course. So it had to be a human--a Settler--posing as a robot. Except even a Settler who had been on the planet five minutes would know that it is impossible for a robot to attack a human. Why bother to plant doctored evidence we will refuse to believe?”

            “That point has bothered me as well,” Donald said. “But even if we assume a Settler was involved in this crime, we must assume that the Settler in question knew more about robots than the average Spacer.”

            “What do you mean?”

            “Consider the detailed familiarity and access to robot equipment required to stage this attack,” Donald replied. “The assailant would have to build and wear shoes with robot foot-tread soles and then replicate the gait of a specific robot. He or she would have to use a surplus robot arm--or an object that closely matched it--as a blunt instrument, and strike in such a manner as to match a blow from that robot arm. He or she would need access to the proper materials to stage the attack, and have the mechanical skill to build or modify the needed robot body parts. To be blunt, sir, a human capable of staging this attack could not possibly be stupid enough or sufficiently ignorant of robots to dream that we would think a robot did it.”

            “But then what was the motive for staging the attack in that manner?” Kresh asked. He thought for a moment. “You said this footprint and arm are off a very standard robot model. How many of them out there?”

            “Several hundred. Several thousand if you include all the variants.”

            “Very well, then. That means there have been several thousand opportunities to steal a robot, or secure a defective one, and strip it for parts--the feet and arms and so forth. Or hell, the assailant could simply get hold of a robot and yank the positronic brain. He or she could plug in a remote-control system with a video-link back to the controller. Let the controller walk the robot body up to the unsuspecting victim--after all, who would suspect a robot?

            “And using a remotely operated robot body that would look like a normal robot would have to be less suspicious than wearing robot-tread boots and carrying a robot arm around. And by working from a remote location, the assailant could hide his or her identity. Another thing: If I popped someone on the head, I’d want to get away fast. Yet those footprints were of a walking gait, not a run. That points toward a remotely controlled robot, one with a fairly limited remote-control system that could manage a walk but not a run.”

            “Except the attacker did not leave immediately. He or she--or it--remained for some time after the attack, at least thirty seconds or a minute.”

            “How do you know that?” Kresh asked. “ Ah, of course, the footprints. They went through the outer edges of the pooled blood, so they had to have been made after Leving had bled long enough to produce a large pool of blood. Damn it! That makes no sense. Why the devil would the attacker stay behind? Not to make sure Leving was dead, obviously, because she wasn’t. But we’re digressing. You suggested that the assailant would know that we’d know that a robot could not commit the crime. Therefore, the assailant had an alternate motive for disguising the attack as coming from a robot. What would that be? Why such an elaborate setup?”

            “To afford the chance to get lost in the crowd later,” Donald suggested. “Let me offer a hypothetical variation on the facts by way of example. We now have an impossible suspect, a robot. Let me offer another impossible suspect to make my point, though I must ask you not to take offense at a hypothetical example.”

            “Of course not, Donald. Go on.”

            “All right. If someone decided to plant clues to make it appear that, for example, you had attacked Fredda Leving, that would limit the search for the assailant to those persons with the ability to plant those clues. Someone who could steal a pair of your shoes, or manage to plant strands of your hair, or your fingerprints, at the scene. But if that someone chose to plant clues that pointed equally well to several thousand identical and impossible suspects--”

            “Our search is made far larger. Yes. Yes, I see that. An excellent point, Donald. But there is still another question. What of the second set of footprints?”

            “If you will grant, for the sake of argument, my original premise, that the effort to make this seem like a robot attack was made because we would know it was impossible a robot did it, I can offer an answer. If we further assume that the motive for that nonconvincing subterfuge was to disguise the real assailant, then I suggest that a single assailant deliberately made one set of bloody tracks, walked far enough that all traces of the blood were worn off, then simply doubled back and walked through the blood again. Again, the idea would be to confuse the search.”

            “It seems an awfully risky thing to do for a fairly minor advantage,” Kresh objected.

            “If, as you suggest, the attacker was using a remotely controlled robot body, as opposed to merely wearing robot boots and carrying a robot arm, there could be no risk in the gambit. At worst, someone might have come in during the assailant’s absence and been there to capture the false robot, with the real attacker at the controls, perhaps many kilometers away.”

            “Yes. Yes. Now they would have us looking for two robots, or two people trying to disguise themselves as robots, when there was really only a single, human assailant. That’s a lovely theory, Donald, just lovely.”

            “There is another note: Our robopsychologists have completed the preliminary interrogation of the staff robots at Leving Labs. Their results are, I think, astonishing.”

            “Are they indeed?” Kresh asked dryly. “Very well, then, astonish me.”

            “First, this is by no means the first time the staff robots have been instructed to stay out of the main wing of the labs. They have been told to get out many times before, usually but not always at about the hour of the attack, but always when the lab was more or less empty. This merely confirms what Daabor 5132 told me the night of the attack. However, the second point provides fresh and remarkable data.”

            “Very well, go on.”

            “Every single robot flatly refused to identify who had given the order. Our robopsychologists unanimously agree that the block restraining them is unbreakable. The psychologists took several robots to and past the breaking point, pressuring them to answer, and all refused to talk right up to the moment they brainlocked. The robots died rather than talk, even when told that their silence might well allow Fredda Leving’s attacker to go free.”

            Alvar looked at Donald in amazement. “Burning devils. It’s almost unheard-of for a block to be that good. Whoever placed it must have done a damned convincing job of saying harm would certainly come to himself--or herself--if the robots talked.”

            “Yes, sir. That is the obvious conclusion. There would be no other way to keep a robot from refusing to assist the police in capturing a murderer. Even so, it would require a human with remarkable skill in giving orders, and an intimate knowledge of the relative potentials of the Three Laws as programmed into each class of robot, to resist police questioning. I would venture a guess that it was only the shock of seeing Fredda Leving unconscious and bleeding that allowed Daabor 5132 to say as much as it did before expiring.”

            “Yes, yes. But why was this order given more than once? Why would the order-giver need that sort of privacy repeatedly?”

            “I cannot say, sir. But the last point is perhaps the most remarkable. The block was placed with such skill that no human at the lab was even aware that the block had been placed. A whole lab full of robot specialists never even noticed that all the robots would not, could not, talk about being ordered to clear off again and again. The degree of skill required to--”

            Suddenly Donald stopped moving and seemed to come to attention. “Sir, I am receiving an incoming call for you from Tonya Welton on your private line.”

            “Devil and fire, what the hell does that woman want? All right, put her through. And you might as well give me full visual.”

            Donald turned his back on Kresh. A flat vertical televisor panel extruded itself from between his shoulders and slid up behind the back of his head. As it rose up, it was showing a shifting abstract pattern, but then it resolved to a sharp image of Tonya Welton. “Sheriff Kresh,” she said. “Glad I got through to you. You should come here, to Settlertown, now.”

            Kresh felt a sharp stab of anger. How dare she order him around? “There’s not that much new at this end, Madame Welton,” Kresh said. “Perhaps if we delayed our next meeting until I’ve had a chance to develop more information--”

            “That’s not why I need you, Sheriff. There’s something you should see. Here, in Settlertown. Or more accurately, over it.”

            Donald spoke, swiveling his head a bit. “Sir, I am now receiving reports from headquarters confirming a disturbance in Settlertown.”

            Kresh felt a knot in the pit of his stomach. “Burning hellfire, not again.”

            “Oh, yes, again,” Welton said, cool anger in her voice. “Deliberate provocation, and I don’t know how calm I can keep my people. Your deputies are here, of course--but it’s worse than last time. Much worse.”

            Kresh shut his eyes and wished desperately for things to stop happening. Not that such wishes were likely to come true any time soon. “Very well,. Madame Welton. We’re on the way.”

MURDER. Riot. What the hell was going on, anyway? Alvar Kresh powered up his aircar and took the controls. It took little more than a glare in Donald’ s direction to make it clear to the robot that Alvar intended to fly himself, just at the moment, and was not going to take any nonsense.

            But still, no sense in getting Donald upset for no reason. Alvar took off, flying with a nicely calculated degree of care, guiding the craft just cautiously enough to keep Donald from taking over.

            Violent crime wasn’t supposed to happen on Spacer worlds. The endless wealth and unlimited prosperity provided by robotic labor was supposed to eliminate poverty, and so remove any motive for crime.

            Nice theory, of course, but it did not quite work out that way. If only it did, Alvar Kresh would have a much more peaceful time of it. For there was always someone relatively poorer than someone else. Someone with only a small mansion instead of a big one, who dreamed of owning a palace. Someone jealous of someone’ s greater affluence, determined to redress the unfair imbalance.

            And no matter how rich you were, only one person could own a given object. Spacer society had more than its share of artists, and thus more than its share of art, some small fraction of it remarkably good. The burning desire to own an original and unique work of art was common motive for burglary.

            There were plenty of other motives for crime besides poverty and greed, of course. People still got drunk and lusted after other people’s spouses, and got into arguments with their neighbors. There were still lovers’ quarrels, and domestic incidents.

            Love and jealousy sparked many a crime of passion, if you could call a crime passionate when it required intricate, detailed planning to arrange for your victim to be somewhere robots weren’t...

            Others broke the law seeking after a different kind of gain than wealth or love. Simcor Beddle, for example. He hungered after power, and was willing to risk arrest--for himself and for his Ironheads--in order to get it.

            And that was just the start of the list of motives. Inferno society was deeply hierarchical, its upper crust burdened with an incredibly complex system of proper behavior. It was vital to keep up appearances, and virtually impossible to avoid making a misstep sometime. In short, upper-class Inferno was a perfect breeding ground for blackmailers and revenge seekers.

            Then there was industrial espionage, more than likely the motive for the attack on Fredda Leving. If there was little original research performed on Inferno, that just made the little that was done that much more precious.

            But none of these motives would have much force if not for another factor, one that, in Alvar’s opinion, few observers and theorists gave anywhere near sufficient weight: Boredom.

            There was nothing much to do on a Spacer world. There were certain personality types that did not adapt well to the endless leisure, the endless robotic protection and pampering. Some small fraction of such types became thrillseekers.

            There was one last thing to throw into the mix, of course--the Settlers. They had been here just over a standard year, and the Sheriff’s Department had never been busier. There had been endless barroom brawls, scuffles in the street, mass demonstrations--and riots.

            Such as the one they were coming up on now. They were nearly at Settlertown.

            Kresh let Donald take the controls. He wanted to be able to see it all from the air, watch the riot in progress, learn the pattern, learn how to counter the Ironheads’ latest moves. He had to keep one step ahead of them, keep them from getting completely out of control.

            Which was ironic, of course, because he believed in everything the Ironheads professed. But a lawman could not let his politics prevent him from quashing a riot.

            Settlertown. Now there was a mad lapse of policy, one that could only result in the sort of strife that had apparently just broken out again. Chanto Grieg and the City Council had granted the Settlers an enclave inside Hades, given them a large tract of unused land, meant for an industrial park that had never been built. If Grieg had to have the damned Settlers on the planet, why in the devil’s name couldn’t he have granted them an enclave well and safely outside the city limits? Putting them inside Hades was an incitement to riot all by itself.

            But no, Grieg let the Settlers in, and the Settlers went to work. And there, coming into view at the horizon, was the result, barely a year after the land was granted. No building in view, of course, but that was deceiving. The Settlers preferred to put their buildings underground, leaving the landscape undisturbed. And if there was no landscape to speak of, why, then, they would build one.

            Alvar’s eyes dropped from the horizon to watch the landscape below. The city of Hades swept past, its proud towers a bit tired and sand-blown, many of its parks faded about the edges, the empty quarters at the edge of town fading from sight on the horizon behind them. And then, up ahead, coming up fast, Settlertown swept to the fore, a sword of green seeming to point at the brown heart of Hades, a huge and idyllic park of great meadows, proud newborn forests of seedlings, the very air over it softened by the mists of its lakes and ponds.

            Incredible, simply incredible, what they had accomplished in a bare year--and without the use of a single robot. Spacers tended to equate robots with machines, and thus Spacers wondered how the Settlers managed without machines. Obviously that was a misconception. The Settlers used highly automated systems and hardware. Those forests had been planted by machines, not stoop labor. The catch was that none of the Settler machines were remotely like Spacer robots. They had virtually no capacity for thought or independent action. The most sophisticated of Settler computer systems would not even register on any of the robotic intelligence tests.

            But the lesson of Settlertown was plain: Dumb machines could do a great deal in the hands of smart, determined people. Alvar Kresh looked down at the green and growing place and wondered: Had there truly ever been a time when the Spacers had been so energetic, so ambitious? What had happened that made the Spacers doze off and let history move past them?

            Yes, Settlertown was a most impressive lesson, but there were those Spacers who did not appreciate being educated. There, near the southern gate of the enclave. A plume of black smoke was rising, a small fleet of sky-blue deputy’s cars circling around it. “Take us in, Donald,” Alvar said, quite needlessly pointing toward the gleam of fire on the ground. Donald was already guiding the aircar down, setting it into a broad circle over the center of the disturbance. Another protest rally against the Settlers, obviously enough. The protesters had a good fire going this time, made out of pulled-up park benches, trash brought along for the purpose, and whatever else burnable they might find. It looked like two dummies of some sort were being dangled in the fire on the ends of long poles.

            Kresh pulled a pair of farviewers out of the aircar’s gearbag and put them to his eyes. “Ironheads,” he announced. “Burning Grieg in effigy again, by the looks of it,” he said, offering the commentary even though he knew perfectly well Donald’s vision was superior to his own. The robot needed merely to increase the magnification of one or both of his eyes. “ And another figure being burned next to him. Maybe Tonya Welton. At least it isn’t me this time. Good.” For a moment, Kresh had feared that word of the attack on Leving had gotten out, in spite of the news blackout he had ordered. But none of the banners he could see mentioned Leving, or anything about the attack.

            Unless the Ironheads had found out about her connection to the Settlers and taken their revenge. That would give them a motive for keeping quiet.

            “Sir,” Donald said, “to the rear of the bonfire--”

            Kresh swung his viewers around and swore. “Burning hellfire, that’s just great. That’ll make the Settlers just happy as could be.” There was a group of masked Ironheads off in a copse of young trees, destroying as many of the saplings as they could, firing point-blank at their trunks with blasters. Not even dragging them back for fuel, which would almost make some sense. But no, this was just wanton destruction for the hell of it. Damned idiots. The Settlers loved their trees, yes, and killing a few would get them mad. But didn’t it occur to the Ironheads that a group of people preparing to reterraform a planet would have the capacity to replace a few trees? And what sort of idiots would kill trees on a planet with a weakened ecology?

            Fools. Maybe, with a little luck, they’d take a few of themselves out with sloppy cross fire. It made Kresh more than a little uncomfortable that he agreed with the Ironhead philosophy. Yes, fine, make more robots, better robots, give the Infernals a real chance to revive the terraforming before handing the job over to outsiders. That all made sense. But politics did not excuse vandalism. Kresh reached for the aircar’s comm mike, but even before he could give the order, one of the circling deputy’s cars dove down almost to treetop level, pumping out a cloud of trank-gas behind itself. The Ironheads scattered, but one or two were dropped by the gas, unable to outrun it. Another deputy’ s car swept down to a landing. Two deputies jumped out and had the unconscious protesters cuffed and ready for pickup in seconds. Their aircar was already back in the air, in pursuit of the escaping Ironheads. Meanwhile, a fire department airtruck was coming in. It fired twin water cannons at the bonfire and the effigies. More deputy’ s cars landed. Deputies poured out and started rounding up the protesters. Good. Good. Kresh was glad to see his people doing so well.

            This was work for humans, no question about it. Riot control was something that robots simply could not do. Which was why, of course, there were still human police. Sheriffs and deputies had to be ready to do a lot of things that broke the First Law.

            Kresh watched his people at work with real pride. There had been no need for him to command or direct. They were getting this sort of operation down to a science. But there was a dark side to that truth. How could they not get better? The devil himself knew they were getting enough practice.

            “Let’s land this thing, Donald,” he said. “ As long as we’re here, we might as well pay a call on Madame Welton. Call ahead to her.”

            TONYA Welton was there on the ground, looking up, watching their aircar land. She was standing by the main entrance shaft to Settlertown, waiting for them. There was something missing about her, Kresh thought, something that should have been there. Then it came to him. Her robot, Ariel. No Spacer would go out of doors without at least one robot in attendance, and in the city Tonya kept to that convention. But here, on her own turf, perhaps she felt she could avoid Spacer absurdities.

            The aircar set down. Man and robot disembarked.

            “Sheriff Kresh, Donald 111,” Tonya said. “Welcome to our humble abode. Come in, come in out of that frightful cloud of smoke your friends have dumped into the atmosphere.”

            “The Ironheads aren’t my friends,” Kresh said, stepping forward. He and Donald followed her into the elevator car for the ride down.

            “No, I doubt that a policeman would approve of their tactics,” Welton said. “But surely you don’t pretend to be opposed to their goals.”

            The doors slid shut, and the elevator began its high-speed descent to the interior of Settlertown. The ride always did odd things to Alvar’s stomach and inner ears. Or maybe it was just that he didn’t like the idea of being a half kilometer underground.

            He shoved those thoughts from his mind and answered the Settler leader. “No, ma’am, I don’t,” Kresh said. “They want you people out of here, they want Governor Grieg to use robots, not Settlers, to reterraform Inferno, and they want Inferno to be a Spacer world, not some half-breed between Spacer and Settler. They believe that such a situation could only be an interlude until your people took over completely. I believe all those things, too. But the ends do not justify the means. Savagery has no place in a political debate.”

            Tonya looked at the Sheriff with a smile that was not entirely at ease with itself. “Well said, Sheriff Kresh. What a pity Chanto Grieg is only a year into his first term. You would make quite an opposition candidate.”

            “The thought had crossed my mind,” Alvar said, drawing himself up to his full height and staring straight ahead. “Someone will have to take him on sooner or later. But the next election will be time enough.”

            “It sounds like an exciting campaign,” Tonya said dryly. The elevator door slid open and Tonya Welton led them out into a large open space underground. It was a huge, vaulted space, to Kresh’ s eye perhaps a kilometer long and half that wide. There was an elaborate false sky overhead which seemed to be mimicking the true conditions in the real sky--from the gleaming sun down to the column of smoke still rising from the direction of the Ironhead demonstration. Welton noticed Kresh looking upward. “Yes, the real-time simulation is a new touch since the last time you were here. The theory is it will be much less disorienting to go back and forth between Settlertown and Hades if our undersky matches the real one precisely. With just the generalized day-night sky program we had before, moving from inside to outside got quite confusing.”

            “Hmmph.” Alvar looked around, feeling most unhappy. perhaps his eyes saw the wide-open spaces of the great cavern, but his mind was aware of every single gram of the millions of kilograms of rock over his head. “I suppose it might help, but I find this place sufficiently disorienting no matter what is projected on your false sky. How can you bear to live underground?”

            Tonya gestured grandly about the huge artificial cavern. Brilliant simulated sunlight shone down on a pretty little park. A fountain jetted a stream of water into the air, a breeze tickled her hair. Small, handsomely designed buildings were dotted here and there about the landscape. “We Settlers are quite used to life below ground. And besides, you can hardly argue that this place is some dank, dismal dungeon. These days, we are able to make our underground homes seem quite like the surface, without interfering with the landscape or suffering the inconveniences of bad weather. Your dust storms cannot touch us here. But we have other matters to discuss. Come.”

            She led them from the bottom of the elevator shaft to a waiting runcart. She sat down in it and waited for Alvar and Donald to do the same. They did so--Alvar next to her in the front seat, Donald in the back--and the cart took off with no apparent command from Tonya. It drove them through the central cavern and into a broad side tunnel. It stopped outside her outer office.

            Alvar resisted the temptation to renew the endless philosophical argument Settlers and Infernals had been having since the day the Settlers arrived. The argument about the cart, and all the other “smart,” nonrobotic, automated hardware the Settlers used. It still seemed suicidally dangerous to trust to automatic devices that did not contain the Three Laws, but the Settlers took a perverse pride in the knowledge that their machines would not prevent people from killing themselves--as if that were a useful design feature. Yes, nonsentient machinery left more scope for human initiative--but what benefit if all that scope gave you was more chances to get squashed like a bug in a crash?

            The three of them disembarked and went through the ornately carved glass double doors into the reception area, and then through to Welton’s surprisingly austere office. Most places in Settlertown were comfortable, even downright luxurious--except for the lack of robots--but Welton seemed to like things kept to a minimum. There was not so much as a desk in the room, at least at the moment, though Kresh knew a worktable could be extruded from the wall quickly enough. There was nothing but four chairs in a circle with a low, round table in the center.

            It seemed to Alvar that the furniture had been rearranged every time he came in here, in accordance with whatever sort of use to which the room was to be put--working office, meeting room, dinner reception, whatever. A Spacer would have had a room for each function. Perhaps this was a cultural holdover from when the Settlers’ underground cities were more cramped. Or perhaps the mock austerity was a mere affectation on Welton ‘ s part. Kresh noted one addition to the room since the last time he had been here. A very standard robot niche, occupied by Ariel at the moment.

            Tonya noticed Kresh looking at Ariel and shrugged irritably. “Well, I had to have some place for her when she is off duty. She herself suggested the niche, and it seemed as good a place as any. I believe she has herself on standby at the moment. Ariel?”

            There was no answer. Kresh raised an eyebrow. “You let your robot go into standby whenever it chooses?”

            “Ariel, poor thing, serves no other purpose than to act as window dressing when I go out among the Spacers. It upsets your people no end to see someone without a robot in attendance. It made it almost impossible to do my work. She calms the passersby a bit. Otherwise, she has no other duties, and I let her do what she pleases. If she wishes to be dormant for a while, so be it. But come, we have much to discuss.”

            Alvar Kresh was more than a bit unsettled by the arrangement with Ariel. Every robot was ordered into standby once in a while, to conserve power or for maintenance, but he had never heard of a robot going into standby on its own. In standby, how could a robot obey the First and Second Laws? Well, no matter, let Welton make her own arrangements. No doubt she told Ariel to choose her own standby times in such a way that Ariel considered it an order. No matter. It was time for business.

            He took a seat, and Tonya Welton took the seat opposite. Donald, as a matter of course, remained standing. But Welton would have none of that. “Donald, sit down,” she said. Donald obeyed and Alvar gritted his teeth, determined not to be annoyed. Tonya Welton knew damn well that it would irritate him to have Donald treated as an equal. She was doing it deliberately.

            “Now then,” she said. “Starting with your Ironheads, Sheriff. This is the most serious and violent demonstration they have mounted. Can you give me any assurance that these provocations will end?”

            Kresh shifted uncomfortably in his seat. “No,” he said at last. “I don’t see much point in my pretending otherwise. There are literally thousands of years of animosity built up between your people and mine. Our people considered yours to be subhuman for a long time, and I suspect ‘some Settlers have had that opinion of us. I think we are all past that stage now, but the fact remains that we don’t like each other. Prejudices remain. There is also a great deal of resentment over the behavior of the Settlers on Inferno.”

            “I cannot see that my people have been overly rude or disrespectful--though I, too, have my uncontrollable hotheads. You picked up a mob of robot bashers just last week. Is it their actions that is causing the resentment? I have done all I could to punish such actions quickly and publicly.”

            “Gangs of drunken Settlers wandering the streets of Hades, destroying valuable robots, have not helped your cause,” Kresh said dryly. “However, I am willing to accept the point that you cannot control your people--the devil knows I can’t control mine. I am even prepared to believe that a terraforming project might well require some rough-and-ready sorts to make it work. The sort that might find ordering a robot to commit suicide amusing.” He glared at her, but she displayed no reaction.

            “None of the bashing incidents have been good public relations for you,” he went on. “But the root cause of resentment is your very presence, your annoying self -confidence that you can so easily solve the climate problems that have bedeviled us.” He made a gesture with his right hand, indicating all of the vast underground settlement he was in. “The casual way in which you built this place was disconcerting. And I might add it seems a very permanent home for ‘a group that does not intend to--ah--settle permanently.”

            Tonya Welton nodded thoughtfully. “I have heard all these points before, and they are good ones. But must we act as if we don’t know what we are doing, just to salve the feelings of the Infernals? We have assembled the finest experts on terraforming from all the leading Settler worlds. They are good, they are skilled, and they brought their equipment. They used it to build their own--temporary-dwelling place. Would you trust the rebuilding of your world to people who were unsure of their skills? Or to people who could not excavate a simple cavern?” Tonya gestured toward Ariel, inert in her niche. “You have seen to it that many of us have robots, to convince us of the worth of your lifestyle. When we go, and leave this place behind as a gift to the city of Hades, we hope that some number of your people will take up residence, and see the advantages of our way of life.”

            “There is little chance of that,” Kresh said, a bit too sharply.

            “There is little chance of Settlers taking home robot slaves,” Tonya countered in an equally unpleasant tone.

            There was a moment’s glaring silence, but then Donald spoke. “Perhaps,” he said, “it might be wise to leave topics of policy for the moment and return to more immediate concerns.”

            Tonya looked toward Donald and grinned. “ Always it comes to this point. You watch the tempers flare, and just when it is about to get out of hand, you politely suggest that your boss and I agree to disagree. I sometimes think you are wasted outside the diplomatic corps. But tell me, does it ever get dull for you, Donald, watching the same tired ritual again and again?”

            “I would not characterize it as tired ritual, nor do I find it dull. Both of you are skilled debaters. I might add that, as a robot programmed for police service, I am a student of human behavior under stress of emotion. I watch, and I learn. It is most instructive.”

            “All right, Donald,” Kresh said irritably. “You‘ve got us both nicely calmed down again. Why don’t we move on to the Leving attack. The Governor’s office hyperwaved confirming orders to me this morning. I am to share all of our information with you. I don’t see why that is needful, but orders are orders. Donald, why don’t you give Madame Welton a summary of our information and theories so far.”

            “Certainly.” Donald turned his rounded blue head toward Tonya Welton and gave a concise summary of the information they had developed since the attack. Tonya asked one or two questions as he went along, and listened carefully. She made no notes, but Kresh had no doubt she was also recording the conversation in some way.

            At last Donald was finished. Tonya leaned back in her chair, stared up at the featureless white ceiling, and thought for a moment before saying anything.

            Finally she looked back toward Donald and Kresh and spoke. “It seems to me that you are going to remarkable lengths to exclude the possibility of a robot as a suspect. Surely you will grant that it requires a good deal of special pleading to accept such elaborate explanations as boots with robot treads or remote control machines that look just like robots. There is an ancient rule of logic that teaches us that, absent compelling reasons to the contrary, it is wisest to use the simplest possible explanation. Taken at face value, the evidence is overwhelming that a robot committed the crime. Why not at least examine that very simple explanation?”

            “Yes,” Kresh agreed uncomfortably,” but the Three Laws--”

            “The Three Laws are going to drive me mad,” Welton snapped. “I know the Three Laws as well as you do, and you need not recite them again like some bloody holy’ catechism. I swear, Kresh, you Spacers might as well face facts and admit that worship of those dismal Laws is your state religion. The answer to all problems, the end of all quests, can be found in the infinite good of the Three Laws. I say that if we just assume that the Three Laws make a robot attack on Leving impossible, I think we are missing a key point.”

            “And what might that be, Lady Welton?” Donald asked mildly. It passed idly through Kresh’s mind that it was well that Donald was around, if only to lubricate the wheels of conversation. Welton had obviously paused for the sole purpose of eliciting the question Donald had asked, but Kresh was hell-damned if he would give her the satisfaction of asking it.

            “A very simple point,” Tonya Welton replied. “With all due respect, Donald, robots are machines, and it is impossible for them to harm humans only because they are built in such a way to make that so. If all runcarts were built without a reverse gear, that would not render the construction of a machine with reverse gear impossible. A machine that is built one way can be built another. Suppose robots were built another way? What is to prevent it--if the builder decided not to follow your precious Three Laws? Would not the rock-hard belief that robots cannot commit such acts provide a perfect cover? The robot’s builder need not even run, for none will think to pursue.

            “One other point. This speechblock put on the staff robots, preventing them from saying who ordered them to go to the far wing of the labs that night. It seems to me that a mechanical device, an override circuit, would be more effective in setting an absolute block against speech concerning certain subjects than in giving an intricate series of orders to each and every robot. It would be easier to set up as well. And before you object that such a speechblock circuit would weaken the robot’s ability to obey the damned Three Laws, we are assuming that the attacker was not too fastidious about such things. Donald--how large a piece of microcircuitry would that take?”

            “It could be made small enough to be invisible to the human eye, and could be wired in anywhere in the robot’s sensory system.”

            “I’ll bet your people never even thought to look for a physical cause for the speechblock, did they? Go over a few of the lab robots with a microscope and see what you find. As to why the perpetrator would need to set blocks for multiple time periods--perhaps he or she wanted some privacy while using the lab’s facilities to make up the attacker robot--or even the robot suit you two are postulating, if you insist that all robots must obey the Laws.”

            There was an uncomfortable silence before Tonya continued. “Even if you do insist on that,” she said at last, “there are documented cases where Three Law robots did kill human beings.”

            Donald’s head snapped back a bit, and his eyes grew dim for a moment. Tonya looked toward him with some concern. “Donald--are you in difficulty?”

            “No, I beg your pardon. I am aware of--such cases--but I am afraid that the abrupt mention of them was most disturbing. The mere contemplation of such things is most unpleasant, and caused a slight flux in my motor function. However, I am recovered now, and I believe you can pursue your point without concern for me. I am now braced for it. Please continue.”

            Tonya hesitated for a moment, until Kresh felt he had to speak. “It’s all right,” he said. “Donald is a police robot, programmed for special resilience where the contemplation of harm to humans is concerned. Go on.”

            Tonya nodded, a bit uncertainly. “It was some years ago, about a standard century ago, and there was a great deal of effort to hush it up, but there was a series of incidents on Solaria. Robots, all with perfectly functional Three Law positronic brains, killed humans, simply because the robots were programmed with a defective definition of what a human being was. Nor is the myth of robotic infallibility completely accurate. There have doubtless been other cases we don’t know about, because the cover-ups were successful. Robots can malfunction, can make mistakes.

            “It is foolish to flatly assume that a robot capable of harming a human could not be built, or to believe that a robot with Three Laws could not inadvertently harm a human under any circumstances. For my part, I see the Spacer faith in the perfection and infallibility of robots as a folk myth, an article of faith, and one that is contradicted by the facts.”

            Alvar Kresh was about to open his mouth and protest, but he did not get the chance. Donald spoke up first.

            “You may well be correct, Lady Tonya,” the robot said, “but I would submit that the myth is a needful one.”

            “Needful in what way?” Tonya Welton demanded.

            “Spacer society is predicated, almost completely, on the use of robots. There is almost no activity on Inferno, or on the other Spacer worlds, that does not rely in some way upon them. Spacers, denied robots, would be unable to survive.”

            “Which is precisely the objection we Settlers have to robots,” Welton said.

            “As is well known, and as is widely regarded as a specious argument by Spacers,” Donald said. “Deny Settlers computers, or hyperdrive, or any other vital machine knit into the fabric of their society, and Settler culture could not survive. Human beings can be defined as the animal that needs tools. Other species of old Earth used and made tools, but only humans need them to survive. Deny all tools to a human, and you sentence that human to all but certain death. But I digress from the main point.” Donald turned to look at Alvar and then turned back toward Welton.

            “Spacer society,” Donald went on, “relies on robots, trusts robots, believes in robots. Spacers could not function if they had no faith in robots. For even if we are merely machines, merely tools, we are enormously powerful ones. If we were perceived as dangerous “--and Donald’ s voice quavered as he even suggested the idea--”if we were so perceived, we would be worse than useless. We would be mistrusted. And who but a lunatic would have faith in a powerful tool that could not be trusted? Thus, Spacers need their faith that robots are utterly reliable.”

            “I’ve thought about that,” Welton admitted. “I’ve observed your culture, and thought about it. Settlers and Spacers may be rivals in some abstruse, long-term struggle none of us shall ever live to see the results of--but we are also all human beings, and we can learn from each other.

            “Of course we came here hoping to convince at least some of you to do without robots. There is no point in pretending otherwise. I have come to see that we are not going to convert any of you. We Settlers could no more wean you away from robots than we could convince you to give up breathing. And I have concluded it would be wrong of us to try.”

            “I beg your pardon?” Kresh said.

            Tonya turned to Donald, stared into his expressionless glowing blue eyes. She reached and touched his rounded blue head. “I, personally, have concluded that we cannot change the Spacer need for robots. To do it would destroy you. To attempt it is hopeless. Yet I am more certain than ever that your culture must change if it is to survive. But it must change in some other way.”

            “Why would you care if we survive?” Kresh asked. “ And why should I believe you do?”

            Welton turned toward Kresh and raised her eyebrow. “We are here trying to pull your climate back from the edge of collapse. I have spent the last year in this sun-baked city of yours rather than back home. That should lend some credence to my claims of sincerity,” she said with a hint of amusement. “ As to why we should care about your culture--would it not strike you as the height of arrogance to assume yours was the only right way to live? There is value, and merit, in diversity. It may well be that the Settler and Spacer cultures together will accomplish things that neither could do by itself.”

            Kresh grunted noncommittally. “That’s as may be,” he said. “But I am no philosopher, and I believe we have covered all the ground we are going to regarding the Fredda Leving case. Perhaps I can send Donald around sometime and the two of you could discuss the whichness of why together.”

            Tonya Welton either missed his sarcasm, which seemed unlikely, or chose to ignore it. She smiled and turned back to Donald. “If you’d ever like to come by,” she said, addressing the robot directly, “I’d be delighted.”

            “I look forward to the opportunity, Lady,” Donald said.

            Kresh clenched his teeth, not quite sure which of the three of them--Donald, Welton, or he himself--had most succeeded in infuriating Alvar Kresh.

            ARIEL’S eyes came to light, glowing yellow. She stepped down from her niche and crossed the room to where her mistress sat. Ariel took up the seat Donald had used.

            “Well, Ariel, what did you think of that?” Tonya asked.

            “I believe it may be easier to get Alvar Kresh to listen than to direct him. I am not a skilled judge of such things, but I do not think he was in the least bit impressed by your arguments regarding the possibility of a--a--robot assailant. Nor do I think he was entirely convinced that I was indeed dormant.”

            “Let’ s get something straight, Ariel. You may not be a judge of human psychology in general, but you know more about Spacer psychology than I ever will. I doubt I’ll ever understand them completely. You were built by them, designed by them, meant to fit into their world. You are the only product of that world I can trust to be loyal to me. You can stand next to me, watching and listening, while they ignore you completely. That’s why I value your opinion.”

            “Yes, ma’am. I appreciate all that. But might I ask--if they all ignore me, anyway, why did you order me to simulate dormancy?”

            “An insurance policy. Kresh was here as a cop, not a Spacer. If you were an even slightly active presence in the room, that could draw his attention to you. If I ordered you out, and you were missing, he might notice that absence, and that would draw attention to you. Besides, I wanted you listening.

            “By telling him I let you go dormant whenever you choose, I drew his attention to me, to the eccentric Settler who treated her robot like an equal. If he thought about you, it would likely occur to him that you had been with me whenever I visited Leving Labs. I do not want you in the hands of Spacer robopsychologists. I’m not the most skilled person in ordering robots. They might easily find ways of getting you to speak about the things I have ordered you not to discuss.”

            “Thank you, ma’am. I understand more fully now. But I must say once again, I do not think he was much impressed by your idea of a robot committing the attack.”

            “Good. I did not expect him to accept the idea. All I wanted to do was muddy the waters.”

            “Ma’am?”

            “I want him worrying about side issues, blind leads. I want to slow him down.”

            “Ma’am, I am afraid I do not understand.”

            “I need time, Ariel. You know as well as I do that I need time to find things out for myself. I have, ah--interests--I wish to protect. “

            Tonya Welton rose, crossed the room, and began pacing back and forth, her actions at last betraying the nervousness Ariel had known was there. “I have interests to protect,” she said again. “He is in hiding, Ariel,” Tonya said, and there was no need for her to speak the man’s name. “He won’t even accept messages from me. That proves something is wrong. He is in danger, and that danger could only increase if his connection to me were revealed at the wrong moment. And I strongly suspect that Alvar Kresh would take a special pleasure in destroying anything--or anyone--that I hold dear.”

            ALVAR Kresh was glad to get out of Welton’s office, to put it mildly. As the elevator arrived at ground level, and he no longer had to hold his claustrophobia in check, he found himself breathing a sigh of relief, and felt his spirits suddenly rise. His anger seemed to fade away into the blessedly open skies.

            “I fear our visit was not especially productive,” Donald said. “Madame Welton did not offer much in the way of useful information or insight, and I do not see what she learned from us that she could not have learned by our sending a data transmission. Nor can I see why our presence was needed at the Ironhead riot. Your deputies handled that without any need of your expertise.”

            “Donald, Donald, Donald,” Kresh said as they walked across the parkland toward their aircar.” And you call yourself a student of human nature. That meeting had nothing at all to do with the exchange of information. Human beings very often are not talking about what they are talking about.”

            “Sir?”

            “We were there not to assist in countering the Ironhead demonstration, but to witness it, and to get the clear message that the Leving case could make such encounters worse. If the populace of Hades gets the idea that Settlers are attempting to discredit robots by staging attacks that seem to be committed by robots, the Ironheads won’t be able to handle all the new recruits.”

            “But what concern is that of yours?”

            “I am in charge of keeping the peace, for one thing. But bear in mind that she chose to meet us on her turf. Up here, on the surface, the air is still smoky, and we’re near enough the perimeter of Settlertown that the air smells of desert again. Down below, all was serene and quiet, and the air was sweet. Another clear message: The Settlers have no reason to fear the rioters. The Settlers can hunker down in their artificial cave. But the citizens of Hades have no such option. And yet the current plans for terraforming all rely on the Settlers. In short, Tonya Welton was telling us we need her far more than she needs us,” Alvar Kresh said as they reached the aircar.

            Donald sat down at the controls and they took off. “Did it strike you as odd that she wished to know so much about the Leving case? After all, she has no responsibility to investigate crimes,” the robot said as he maneuvered for altitude.

            “Yes, I wondered about that. In fact, I rather got the impression that she was waiting for us to say something we didn’t, though the devil alone would know what that might be. I don’t know, Donald. Perhaps she has some genuine personal or professional interest in Leving’s well-being.”

            “I see,” Donald said, some trace of uncertainty in his voice. “But I don’t regard that as a sufficient explanation of Lady Tonya’s strong interest. Note that she scarcely asked at all about Fredda Leving herself. It was only the robotic aspect of the case that interested her. Why does she care so deeply about the case, and why does she regard it as so overwhelmingly important?”

            “I tell you what I think, Donald,” Kresh said as he watched the landscape below. “I think a Settler committed the crime, perhaps acting directly under Tonya Welton’s orders, precisely to set off more disturbances and give the Settlers an excuse to get off the planet. Bringing us in today during the riot was merely the first step in orchestrating that withdrawal.”

            “Might I ask your reasons for thinking that?” Donald asked impassively as he guided the aircar.

            “Well, first off, I don’t like Settlers. I know that’s not much of a reason, but there it is. And second, say what Tonya Welton will about this contingent of Settlers being trained to understand our ways and appreciate the Three Laws, I still can’t believe a Spacer would try any of the stunts that have been suggested to explain the attack. Think about them: building a remote-control device that mimicked a robot, strapping on robot feet and using a robot arm as a club, building and programming a special-purpose killer robot. No Spacer would do those things.

            “Welton was right about one thing--the Three Laws are close to being our state religion. Interfering with them, abusing them or the concept of robots in any way, would be close to blasphemy. There are times when I think our illustrious Governor Chanto Grieg is pushing so hard for change that someone’s going to bounce up and call him a heretic. Maybe it even goes deeper than that. I find the very idea of perverting robots to be stomach-turning. It’s like the prohibition against cannibalism or incest. I doubt any Spacer unbalanced enough to make the attempt would still be sane enough to do all the methodical planning required.

            “No. Only a Settler would be stupid enough--well, all right, ignorant enough--to try and plant the idea that a robot could commit an act of violence. Any Spacer would know how deep and abiding the prohibition against that is.”

            Alvar stopped and thought for a minute. Suddenly a new and disturbing thought dawned on him. “In fact, that might well be the motive. Maybe the Settlers don’t want to leave. We’ve been too tied up with figuring how the attack was made to stop and wonder why anyone would want to attack Fredda Leving.”

            “I’m afraid I don’t follow you, sir,” Donald said.

            “Let’s just ignore all of Welton’s nonsense about respecting us as an alternate culture. She as much as said they came here as missionaries, hoping to convert us away from robots. The Settlers--this lot on Inferno, and all of them generally--are always casting about for ways to make the Spacer dependence on robots look like a weakness, instead of a strength. Trying to convince us to abandon robots. You spoke about the need for us to trust robots. Suppose the attack on Leving is the opening salvo in a campaign to make us afraid of our own robots?”

            “I see the point, sir, but I am forced to question the choice of Fredda Leving as the victim. Why would the Settlers attack their own ally?”

            Kresh shook his head. “I don’t pretend to understand their politics, but perhaps there is some sort of bad blood between Welton and Leving. Some sort of resentment, some sort of competition or disagreement between them. Jomaine Terach hinted at it. It must be tied up in this grand project we can’t be told about yet.

            “And I don’t think we’re going to get anywhere until we know what that’s about.”

            THREE hours later, Alvar Kresh sat at his desk, reading through the daily reports, making notes to himself on the status of this investigation, that application for promotion. By rights, he should have gone home to bed, allowed himself some rest. All told, he had gotten perhaps an hour’s sleep the night before. But he was too keyed up to sleep, too eager to leap back in and get on with the chase.

            Except, as yet, there was nothing to chase. Until and unless Gubber Anshaw emerged from his home, Kresh would be unable to question him. Maybe the forensic labs would be able to come up with something as they sifted through all the physical evidence at the scene. Kresh had a bet with himself that forensics would come up with something--but that it would be misleading. Whoever had done this thing seemed damned clever at leaving clues that did not point anywhere.

            But until something broke with a witness, or evidence, there was damn little he could do.

            No, there was one other possibility. There was always the chance of another incident. Another attack that could give him a pattern, a rhythm, he could work with. Another attack carried out a bit more sloppily. It was a terrible thing for a policeman to wish for a new crime to be committed, but there were precious few other ways he could get a break on this case. What else could he do? Send half the force out randomly searching for robot-soled boots? Surely the perpetrator had destroyed them by now, or else hidden them well indeed, ready for the next attack.

            Alvar struggled to get his mind off the case. After all, he did have a department to run. He managed to get through a worrying report from personnel, regarding a sudden uptick in the number of resignations from the force. But his resistance to distraction did not hold for long. Even that report, with its hints of a danger to the whole future of the department, did not occupy the whole of his mind.

            Because the Settlers were here to take over. He knew that much, deep in his gut. No matter how many denials or reassurances they made, no matter how much noise Governor Grieg made about rapprochement and new eras of cooperation, Kresh would still believe--would still know--the Settlers looked at Inferno simply as a world ripe for colonization.

            For the time being, the Settlers--at least most of them--were making polite noises, being respectful of local culture, but that would not last. Local culture. There was a political code word, if ever there had been one. A euphemism for the use of robots. Some optimists thought that the Settlers on Inferno would grow used to robots, come to see the advantages of robots, and perhaps even return home to their Settler worlds singing the praises of robots. A market would develop for Spacer robots on Settler worlds, and everyone would get rich selling robots to Settlers.

            But Kresh had no such illusions. The Settlers were here to take over, not to be sold serving robots. Once they were firmly in control of Inferno--well, all it took to be done with a robot was a single shot from a blaster. After they had wiped out the robots, the Settlers wouldn’t even need to move against the Spacers. Spacer culture--and individual Spacers--needed robots the way a person needed food and drink. Too many jobs were given over to robots, too many people had never bothered to learn tasks that were more easily left to robots. Without robots, the Spacers were doomed.

            Which brought him back to his central point: What happened to Spacers if robots could no longer be trusted?

            And what if the Settlers engaged in a plot for the express purpose of finding out?

            BLEND in, Caliban told himself. Observe what the other robots do. Behave as they do. Already, he had developed the sophistication to know his very survival might depend on acting like the others. He walked back and forth across Hades, watching and learning, shuttling back and forth across the city as day crossed the sky and night came on.