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 todo 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 fewtrees? 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 theirgoals."

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 havesome 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 builtthis place was disconcerting. And I might add it seems a very permanent home for 'a group that does not intend to-ah-settlepermanently."

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 ofour 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 ifhe 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 humansonly 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 machinewith reverse gear impossible. A machine that is built one way can be built another. Suppose robotswere 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 robotscannot 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 aphysical 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 thatall robotsmust 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 culturemust 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 assumeyours 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 aboutSpacer 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, whilethey 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, andthat 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 aboutyou, it would likely occur to him that you had been with me whenever I visited Leving Labs. I donot 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-Iwish 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 fromme. Thatproves 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 towitness 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 onher 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 Settlersdon't want to leave. We've been too tied up with figuring how the attack was made to stop and wonderwhy 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-arealways 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 Levingis 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 whatthat's about."

THREEhours 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 nothingto 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 knewthat 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 stillknow- theSettlers 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 evenneed 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.