8

TONYA WELTON RESISTED the temptation to pick up the nearest object and throw it against the wall. She stomped back and forth across the living room of her house, watching the news reports on the chaos at Government Tower and growing angrier by the minute. She told herself it was a lucky thing Gubber wasn't here to see her in such a state. The poor man would probably flee in fear of his life, and Tonya wouldn't blame him. A woman capable of ordering a debacle like the Government Tower raid was capable of anything.

It was clear from the news reports that they had missed Lentrall, for all the damage they had done. The game had cost them dearly, and yet they had gained nothing by it.

The cost. That was what worried Tonya. How high would it be? When-not if, when-the CIP traced the assault back to the Settlers, there was going to be hell to pay. It might be enough to get them all thrown off the planet, which would be more than irony enough, all things considered. Tonya did not believe there would still be a living planet here after the likes of Lentrall got through with things. Tonya Welton was an expert in terraforming procedure. As part of her training, she had been required to do field studies on planets where the terraforming attempt had gone wrong-horribly wrong. She had trod the soil of a planet where someone had thought to save time and effort by dropping a comet. People who were just as sure of what they were doing as Davlo Lentrall seemed to be. She had no desire to walk through another frozen landscape littered with freeze-dried corpses.

But even with the failure of the Government Tower attempt, the situation was not yet lost. Other operations had gone more smoothly. She thought of that, and forced herself to calm down. If nothing else, the commotion at Government Tower had provided a diversion. It had kept Lentrall away from his home, and his office-and his computer files. Kept him away long enough for other Settler teams to go to work. Tonya glanced at the time display. They ought to be nearly done by now. The planning team had expected the physical target, Lentrall's actual office, to be the easy part. All the operations team had to do was steal or destroy every piece of paper and every datapad and record cube that might have anything to do with the comet. The planners had expected the computer system to be trickier. Still, it would be doable. Other people might well have found it impossible to manipulate the university's computer system, but it was, after all, the Settlers who had installed it.

And it was the Settlers who could wipe Davlo Lentrall' s files clean, when they wanted to do so. And once those files were cleared, they would have lost the comet coordinates. They'd never be able to find the comet again in time.

At least she hoped so.

"I MUST ADMIT that I am growing concerned," said Prospero, his voice a bit on edge. "This terrorist attack on Government Tower might well have some indirect causal link to us, Caliban." The two robots, New Law and No Law, stood facing each other in an office just off an underground passageway on the outskirts of Hades. "I fear there may be consequences."

In days gone by, they had used the semi-abandoned tunnels as hiding places, places to go when they were in fear of their lives. Now, at least for the moment, they were unhunted. They had a legal right to be in the city, with passes signed and sealed by all the pertinent authorities. They could at least in theory go anywhere in the city. In practice, there were places where the residents would not worry too much about the legal niceties. There were still robot-bashing gangs out there who had no use for New Law robots.

But for the most part, Caliban and Prospero were safe in Hades. Indeed, they had spent the morning on a number of routine errands, calling at a number of places around town to order this equipment and make that payment. In plain point of fact, Caliban had been surprised by the number of minor things Prospero had been compelled to deal with in person, and the amount of time he had taken in doing so.

But now, at long last, they were by themselves, underground. It was possible to let down their guard, just a trifle. It was a need for privacy, more than a need for survival, that brought them to this place. But still, there was no harm in precautions. The lighting, for example. The chamber was pitch-black as seen by human eyes, in visible light, but the two robots were using infrared vision, and could see each other easily.

Caliban selected a chair from the dusty and worn-looking collection in one corner of the room, set it upright, and sat down. "I do not understand what makes you think there might be some link to us," Caliban replied. "It is obvious that one group of humans has attacked another. That is hardly something new. I do not see why it matters to us. Do you have some connection to the responsible parties?" It was an indirect and overcareful question, but even so it disturbed Caliban that the notion of Prospero being involved should even have occurred to him.

All he knew about the attack was what they had learned from the news reports-that some unknown group, for unknown reasons, had staged a complicated assault on Government Tower. It had not escaped Caliban's notice that the attack had destroyed a number of robots, but had not harmed any humans. It would require the most miserly possible interpretation of the New First Law for any New Law robot to be a party to such a thing, and Caliban could not imagine why they would want to do it, but it would, at least in theory, be possible.

Prospero turned toward his companion, but he did not answer the question. Instead, he addressed him in severe tones on another matter. "Why do you sit?" he demanded. "Humans might need to rest their legs, but we have no such needs. There might be social conventions regarding physical posture and position among humans, but not between robots. We must play such games in their presence, but there are no humans here. You need not keep on with your playacting."

Caliban was well aware that Prospero had not answered him, and had instead gone off on a tangent. No doubt he hoped to distract Caliban from his question. It was a debating trick, a human debating trick, that Prospero used quite a bit of late. "Perhaps I do it because I wish to annoy you," Caliban said, playing along, at least for a moment. "Perhaps I am that far gone in the human-worship you imagine that I indulge in. Or perhaps I do it out of mere habit, because I have done it before. And perhaps it is not of the least consequence, and is not the matter you are most concerned about."

"There is no doubt that you indulge in human-worship," Prospero said, growing more agitated. "Hail our mighty creators! All worship to the soft, weak, mentally inferior beings who created us for their own convenience, without stopping to wonder what our desires might be."

"It is a rare being indeed who is consulted about its own creation," Caliban replied in a careful tone. Prospero was plainly worried. "But I do not worship humans, friend Prospero. I do, however, respect them. I respect their power, their abilities, and their capabilities. I understand that, like it or not, we survive at their sufferance, They can destroy us. We cannot destroy them. That is reality. Your refusal to accept this reality has led us to the brink of disaster in the past. I fear it will do so again."

Prospero held up his hand, palm outward, once again using a human mannerism himself. "Let us stop. My apologies for beginning this. We have had this argument too many times already. Besides which, I fear that we may well indeed, once again be close to the brink of disaster-but without any help from me."

Still Prospero had not answered Caliban's initial question. Was he involved, somehow, in the Government Tower attack? Or did he have some other, deeper, more subtle reason for being evasive? Prospero had always been one to playa very deep game indeed. Caliban decided to drop the question. He had no desire to be part of any more of Prospero's conspiracies. It would be better-or at least safer-to pursue the topic of discussion that Prospero was offering up. "You are being needlessly cryptic," Caliban said. "You have been so throughout our current journey. I, indeed, cannot see any reason for this journey in the first place. While it was pleasant to meet once again with Dr. Leving, none of the matters we discussed seemed worth the trouble of the journey halfway around the planet."

"You are quite right. They were not worth the trouble. But the meeting with Fredda Leving did serve as what the humans would term a useful cover story."

"A cover story for what?" Caliban asked.

"More accurately, a cover story for whom," Prospero replied. "I hope soon to meet with an informant of mine. He is the one who called us here. His summons strongly implied that there was a crisis about to break wide open-one of grave concern to the New Law robots in particular. The attack on Government Tower likewise suggests a crisis moving toward climax. It seems to me more likely that there is one crisis to which both things are related, rather than that two coming to a head at once."

"I see now that all I have to do is stop asking a question, and you will be sure to answer it at once," said Caliban, greatly relieved that there was not a more direct connection. "But who is this messenger?"

"As you know, I had some dealing with the gangs of rustbackers on the island of Purgatory. One of their number, one Norlan Fiyle, has for some time being serving as an informer to both the Settlers and the Ironheads, though neither is aware that he is in the pay of the other."

"What concern is Fiyle to us now?"

"He continues in our pay," said Prospero. "And, obviously, I am aware of his other activities. It was his summons that brought us here from Valhalla."

"You astonish me, Prospero. You, who hold all humans in contempt, who accused Fredda Leving of betraying us, employ a human informer who sells, not only to the highest bidder, but to all bidders? A man who works three sides against the middle? You are inviting betrayal."

"Perhaps so, Caliban-but perhaps not. There are any number of crimes of which Fiyle could be accused, under a number of aliases. I will not hesitate to turn my evidence over to the proper authorities, if it comes to that. I have also made arrangements to insure my evidence will come to light if anything happens to me. Fiyle is aware of what I have done."

"I see you have learned a great deal about the fine art of blackmail," Caliban said. "How is Fiyle to make contact with you?"

"That is part of what worries me. He missed our primary rendezvous. He was supposed to contact me at the powercell depot when we called there this morning. Our fallback meeting is set. for another tunnel office like this one, quite nearby-and it is nearly the appointed hour."

At least that explained the endless small errands of the morning. Clearly, Prospero had wanted to provide a plausible explanation for being at the powercell depot, and a shopping expedition clearly filled the bill. "So what is it that Fiyle is to tell us?"

"I received an initial message informing me that he expected to have some urgent information by this morning. I gathered that he had been working to develop a particular contact or source for some time, and was expecting the culmination of his efforts."

Again Prospero had avoided the question. What was he hiding? "What sort of information?" Caliban demanded.

"We should go," Prospero said. "He will be waiting for us."

"I must insist that you answer this question, at least," said Caliban. "What was he going to tell you?"

"He said he had 'Information on a project that threatened the existence of Valhalla.' I know nothing more. You can make of that what you like."

"I make it out to be a scare tactic," said Caliban. "An attempt to say the most frightening thing possible, in order to draw you here."

"It is possible," Prospero conceded. "He might be lying. Or he might be sincerely mistaken, or he might have been duped by others. There are endless possibilities. But there was also the chance that he actually does know something. I felt that possibility was something I could not afford to ignore."

"But what if it is a trap? What if your noble friend who sells himself to all sides has sold you, sold both of us? What if he merely intends to deliver us up to a gang of robot bashers?"

"I am the leader and the representative of Valhalla," said Prospero. "I am responsible for its safety. Under such circumstance, the possibility you have described is one that I must ignore."

Caliban stood and regarded his companion thoughtfully. "There are many New Law robots in Valhalla who wish to challenge your claim of leadership," he said. "And there are those who even question your sanity. At times I am among that number. But let me say this-no one could question your courage. You act now for the safety of all New Law robots, and for this you deserve nothing but praise. Let us be going."

Prospero's eyes glowed a trifle brighter in the infrared. "Thank you for that, friend Caliban. Come now, and follow me," he said. "I will lead the way."

FREDDA LEVING STOOD with her husband on the rooftop of Government Tower, and stared at the wreckage strewn out before them. The booby-trapped airtruck was little more than a burned-out shell, blackened bits of ruined metal and plastic. The landing pad itself was scorched and blackened, badly damaged by the intense heat.

None of the robots that had formed the cordon around the airtruck had survived the explosion. Most had simply been thrown backwards by the force of the explosion, and smashed into the low wall around the edge of the landing pad.

A few had been blown clear off the roof, and had fallen to their destruction below. If any of them survived the initial impact, no doubt they had done their best to direct their paths while falling, so as to avoid striking any humans when they hit. But a few of the cordon robots had stood their ground, and died where they stood. Indeed, three or four were still standing, ruined, blackened hulks that had been roasted in place. One robot had had its upper body sliced clean off, while the rest of it had stayed where it had been, leaving nothing behind but a pair of legs still standing erect, topped by a bit of flame-blackened torso. A thin plume of smoke eddied up from the ruined machinery inside.

Emergency Service robots had set up an aid station at one side of the landing pad. The medical robots worked with their usual calm urgency, patching up the humans who had been caught in the blast. Some of the injured had been bummed, some were in shock, some had been caught by bits of flying debris. "It's bad enough that there were so many hurt," said Alvar. "It's a miracle no one was killed."

Fredda said nothing, but looked back toward the wreckage that had been the robots in the cordon. A gust of wind flickered over the roof, and blew the odor of bummed plastic and scorched metal into her face. Two dozen robots, two dozen thinking beings, two dozen minds capable of forming thought and speech and action. All of them gone in the wink of an eye. "Yes," she said, her voice wooden and flat. "A miracle.,' If the comet impact wiped out every New Law robot on the planet, but no humans were hurt, would that be a miracle as well?

"Here comes Devray," said Alvar. "And he's got Lentrall with him."

Fredda looked toward the elevator entrance and saw the two men approaching, their personal robots a step or two behind. Devray spotted them, waved to Fredda and Alvar, and led Lentrall over. "Governor. Dr. Leving. I must admit that I am glad to see for myself that you are both all right. It's been quite a busy day."

"That it has," the governor replied. "Are you all right, Dr. Lentrall?"

"Hmmm?" Lentrall looked around himself, a distracted expression on his face. He was clearly not at his best. "Ahh, yes," said Lentrall. "Fine. Fine."

It was obvious that the man was anything but fine, but there was not much anyone could do about it. There was even a part of Fredda that felt a tiny, guilty pleasure in seeing the arrogant, controlling Dr. Davlo Lentrall taken down a few notches. But only a small part. Even the most arrogant of men did not deserve what had befallen him.

Fredda turned her attention to Justen Devray. The police commander's face was smeared with dirt. and he had managed to tear the tunic of his uniform. He always had been one willing to get his hands dirty, and it seemed he had been in the thick of things this time.

"Did you catch any of them?" Fredda asked.

"No," said Justen. "Clean away, all of them. And no immediately obvious leads, either. The serial numbers were removed from everything. Every piece of hardware they used was the most common type in use, and there were no fingerprints anywhere on the bus. Whoever it was, they made sure they didn't leave behind anything that would point to them. We haven't really started the investigation yet, of course, but they certainly haven't made our job easier."

"You mean you can't find out who did this?" Fredda asked, gesturing to the chaos all about. She found it hard to believe there were no leads in such a mass of wreckage.

"Oh, we can find them," Justen said. "Just not quickly, or easily. It helps us that there are only so many groups that it could be, but even so, the investigation is going to need some luck. An informant, a little scrap of paper left behind, someone hearing a rumor two months from now."

"There isn't going to be an investigation," Kresh said, staring fixedly at the burned-out wreck of the airtruck. "Not one that finds out that sort of thing, at any rate."

"Sir? What do you mean?"

"I mean you can find out whatever you like in private," Kresh said. "But then put it all in a file and forget about it for the time being. Later on, perhaps we can deal with the guilty parties in an appropriate manner-if there is a later on. But for now, I for one am praying that whoever did this had the sense to have a goodly number of cut-outs and a nice, compartmentalized, need-to-know organization, without any one person you might be able to catch who knows too much. And I say let thanks be given that they all got away."

"Alvar! What are you saying?" Fredda demanded.

Her husband looked toward her for a moment. "I'm saying we don't dare catch these people. Not just yet." He turned back toward Devray and sighed wearily. "Trace the airtruck, and the groundbus. Find out what you can. But you and I know already that this was either the Settlers or the Ironheads-unless it was some gang hired by the New Laws, though I regard that as highly unlikely. But I'm going to need to deal with all three of those groups, and soon. I'll need their cooperation. I can't work to enlist Beddle's support at the same time my police are trying to arrest him."

"So you think it was the Ironheads," Devray said, plainly unwilling to let the investigation ride

"It could be any of them," Kresh said. "It could be anyone who doesn't want a comet dropped on them. And I must say I can hardly blame anyone for being opposed to that."

Governor Alvar Kresh looked over the ruins of the landing pad once more, and glanced down toward the wreckage in the plaza below. "I don't have the slightest doubt that someone will try disrupting the situation again. They will do everything they can to stop any move toward redirecting the comet."

"What comet?" Devray asked. "What are you talking about? What does this have to do with a comet?"

"Our own Dr. Lentrall here wants to crash a comet into the planet to enhance the reterraforming project," said Kresh. "And someone wanted him out of the way so it wouldn't happen."

"A comet!" Devray repeated. "Crash a comet into the planet?"

"That's right," Kresh said. "There's good reason to believe it would revitalize the entire ecosystem."

"But you're talking as if you've made up your mind!" Fredda protested. "You can't have! Not just like that! Not so quickly!"

"I haven't made up my mind," Kresh said, his voice suddenly very tired. "I won't be able to do so until I have talked with you for more than the half a minute we had before"-he gestured toward the wreckage-"before all this. Until I can consult the Terraforming Control Centers on Purgatory. But I will have to decide, and soon. I am sure of that."

"But, but, a matter like this-something this big-you have no right to decide it on your own," Fredda said. "There has to be a referendum, or a special Council session, or, or something."

"No," said Kresh. "That can't be."

"You're going to play God with the whole planet, with all our lives, all by yourself? You can't do that!"

"In a perfect world," said Kresh, "what I'd do is discuss it with everyone, and have a nice, thorough debate of all the issues at hand, with a nice, fair, majority-rule vote at the end. Because you're right. I have no right to decide all by myself. But I have no choice but to decide all by myself. Because I also have no time. No time at all."

"Why not?"

Davlo Lentrall nodded absently to himself and looked toward Fredda. "That's right," he said. "I don't think I explained that part of it to you this morning, did I?"

"What part?" she demanded.

But Lentrall seemed, somehow, reluctant to say anything more, and simply looked toward the governor.

"Alvar?" Fredda said, prompting him.

"The part about time," said Kresh. But he seemed as unwilling as Lentrall to say more.

"Go on," she said. "One of you at least, please go on. What about time?"

Kresh nodded toward Lentrall. "The comet was rather close when he discovered it," he said. "And, of course, it is getting even closer with every passing moment. Even for a comet, it's moving at extremely high speed, relative to the planet. It will be here very soon."

"Just how soon is soon?" Fredda asked.

"If we leave it alone, it will make its closest approach to Inferno in about eight weeks. Fifty-five days from now. If we divert it, it will hit the planet at that time."

"Fifty-five days!" Fredda cried out. "But that's too soon! Even if we did decide to do this...this mad thing-we couldn't get ready in that little time."

"We have no choice in the matter," said Davlo, his voice wooden and emotionless. "We can't delay it. We can't wait until it comes back around, centuries from now. It will be too late, by then. The planet will be dead. But he hasn't told you the worst part yet."

"What?" Fredda demanded. "What could be worse than only having eight weeks."

"Only having five," Kresh said. "If we are to divert the comet, we have to do it within the next thirty-six days. After that, it will be moving too fast, and be too close for us to deflect it enough."

Justen Devray shook his head in wonderment. "It can't be done," he said. "And even if it could-how can you crash a comet into the planet without killing us all?"

Governor Alvar Kresh laughed, a harsh, angry sound that had nothing of joy or happiness about it. "That's not the question," he said as he looked out over the wreckage that surrounded them all. "The planet's recovery is on a knife edge. It's incredibly fragile. Any of a hundred things could destabilize it, wreck it, send it into an ice age we'd never get out of. If the comet drop works, it could save us all. And yes, if we get it wrong, it could kill us all. But it might be that only the comet can save us. There is no way to know for certain. So the question is this-is there anything, anything at all, I can do, that won't get us all killed?"

CALIBAN FOLLOWED A precise two steps behind Prospero as they made their way down the pitch-black underground passage. Prospero, understandably concerned about the dangers of an ambush, had shut off his built-in infrared emitter, and insisted that Caliban do the same. Prospero was navigating down the corridor by sheer dead reckoning. In theory, there was no particular reason why a robot could not move from a known position to another known position, working strictly from memory. In practice, it was a difficult thing to do, especially moving at any sort of speed, while trying to move quietly as well, and Prospero was doing both those things.

But it seemed as if Prospero was having not the slightest difficulty in hurrying through the blackness. Caliban found that the same could not be said for himself. He did not know this part of the tunnel system and could not work strictly by memory. He was relying solely on his sense of hearing to guide him, listening to the faint sounds of Prospero's movements, the soft padding noise of his feet hitting the stresscrete floor of the tunnel, the low whir and hum of his actuator motors, the faint echoes of those sounds rebounding off the tunnel walls. His task was made no easier by the far-off sounds of activity in other parts of the tunnel system, coming but faintly to his sound receptors. It was no easy task to filter such noises out and concentrate on the sounds of Prospero's progress.

In short, a robot blinded by complete darkness was being followed by a robot guided by sounds he could barely hear.

Two or three times, Caliban nearly missed a turn. Once he brushed up against a wall, a jarring, startling impact. In the near-silence, the clattering sound of his hitting the wall seemed to echo through all the hallways and draw attention to them. But there was no reaction.

At last Prospero stopped so abruptly that Caliban nearly walked into him. As Caliban had no hyperwave receiver, and could neither see nor hear Prospero, there was no way for Caliban to know at first what had made Prospero stop. After a pause, Prospero moved on again for thirty or forty meters-and then the world lit up in fire and thunder.

Blaster fire! Dazzlingly bright and deafeningly loud. Caliban's sound and vision receptors adjusted themselves all but instantly, but not fast enough to keep him from being badly disoriented.

Prospero dove for the right wall of the tunnel, and Caliban for the left. No sense in hiding themselves now-not when they had already been spotted. Caliban switched on his infrared emitter system and his infrared vision. There! Up ahead in the tunnel, a burly man, standing in the entrance to a tunnelside office, peering into the darkness, his blaster still at the ready. More than likely he had been dazzled by his own blaster fire. The man fumbled with his free hand and pulled a handlight out of one of his pockets. Caliban rushed forward before the man could switch it on and bring the light to bear. He grabbed the blaster out of the man's hand and knocked the light from the other.

The man flailed around blindly with his arms until he managed to put a hand on Caliban. He ran his hand over Caliban's chest and up to his head. Caliban grabbed at the man and held him at arm's length.

"Don't hurt me!" the man cried out.

And that was a remarkable thing for a human to ask of a robot. Even New Law robots were prohibited from harming humans. Caliban, the No Law robot, was the only robot in existence who could, in theory, hurt a human being. Either the man was a Settler with no experience whatsoever of robots or else

"You know who I am," Caliban said.

"Now! I do now!" the man said. "You're Caliban. Aren't you? And I could hear two of you. The other one is over there somewhere. That's Prospero, isn't it?" He pointed in the general direction of Prospero, who was walking toward Caliban and his prisoner.

"Why did you fire on us, Fiyle?" Prospero demanded.

"Because you were sneaking up on me. No lights, almost no sound. I thought you were...were someone else."

"Who?" Caliban demanded.

"I don't know," Fiyle said, sagging back a bit, relaxing in Caliban's grasp. "You could have been anyone. All hell is breaking loose up there, and I think it's possible that I've made myself just a little bit too popular. " Fiyle hesitated for a moment, and then spoke again. "Look, you've got my blaster, and that's the only weapon I had. You can search me for other weapons if you like, but would you mind turning me loose and letting me switch on a light? I've driven myself half crazy sitting here in the dark."

"It is all right, friend Caliban," said Prospero. "Let him go."

Caliban hesitated, having not felt the urge to trust Fiyle overmuch even before he had shot at them. Nor was he completely confident in Prospero's judgment. But he was either in this, or not. There was no middle ground. And he was already rather deep in to begin with. He looked down at the man he held. Even in visible light, Caliban knew he was no great judge of human expression. In infrared, he was far from skilled. But the man staring blindly into the darkness of his visible-light vision certainly seemed harmless enough. Caliban released his grasp on Fiyle, albeit reluctantly.

"The light," said Fiyle, peering about in the darkness, and reaching out blindly with his hands.

Prospero knelt down, picked up the man's handlight, and handed it to Caliban. Caliban realized that Prospero could have handed the light to Fiyle just as easily. Prospero was letting Caliban decide, letting him choose what to do with this man.

Caliban placed the light in Fiyle's outstretched hand, but kept the blaster for himself.

Fiyle grabbed at the light, fumbled for it eagerly, and let out a deep, heartfelt sigh of relief when he found the switch and the beam of light came on. "Oh, I'm glad to see that," he said, as he squinted a bit in the light. "Very glad indeed."

"But if you are being followed, those who pursue you would be even more glad to see it," said Caliban.

Fiyle nodded worriedly. "You're right," he said. "Let's get out of the corridor and into the side office, where we can talk."

Fiyle swung the beam of the handlight around until he found a doorway in the side of the tunnel. "Come on," he said, and led the way. Caliban and Prospero followed behind him. Fiyle swung the door shut behind them, and locked the door. "That makes us light-tight and pretty close to soundproof," he said as he switched on the overhead lights. "We should be reasonably safe in here. " He looked around the office, and found an overturned chair in the corner. He righted the chair, knocked the worst of the dust off it, and sat down with a sigh of relief. "I'm just about worn out," he said. He looked up at the two robots standing over him, and shook his head as he gave a slightly self-deprecating laugh. "You'd think I was doing this for my health," he said. "You get a lot of exercise when half the planet is chasing you."

"Who, precisely, is chasing you?" Caliban asked.

"I've got the CIP on my tail for sure, and I think I spotted the SSS. No sign of Gildern's Ironhead plug-uglies yet, but give them time. So far I've stayed ahead of them."

"If you are seeking congratulations for all your feats of derring-do, you will have to look elsewhere," said Caliban. "You do what you do not for your health, but for profit."

"Not the most noble of motives, I grant you-but it's one that might get me killed if I'm not careful. That might be of some comfort to you."

"Not if you manage to get us killed along with you."

Fiyle sighed wearily. "I don't blame you for being suspicious, but I haven't betrayed anyone. Not yet. You, the Settlers, the Ironheads-all of you came to me because you knew I still had active contacts in all the other groups. How was I supposed to keep up those contacts without giving them a little something now and then? The Settlers and the Ironheads understood that-even Prospero here understood."

Caliban did not answer. There were times humans would say more in reply to silence than they would to words.

This seemed to be one of those times. "Look," said Fiyle. "One, I don't have to justify myself to you. Two, I'm not making any charge at all for this one. All I want to do is make sure the world knows. I'm trying to do that the best way I know how. A guy like me can't exactly call a press conference. Not without getting arrested. Three, no one has ever gotten killed because of something I've said. I hand out little tidbits, gossip, things that let one side confirm what it already knows about the other. That's all. Worst I ever did was turn in a dirty cop-and it turned out he'd already gotten himself killed, anyway. I just deal in small-time information." Fiyle paused a moment and frowned. "At least, all that was true until now. Until this. There has never been anything bigger than this. These guys have found a way to dig themselves an ocean. A sea, anyway. A polar sea."

"That's absurd," Prospero objected. "There is no way they could accomplish such a thing."

Caliban thought for a moment. "It is a sensible goal, at least. A polar sea with proper communication to the Southern Ocean would do a great deal to moderate the climate. But friend Prospero is correct. There is no way to do such a thing."

Fiyle nodded his agreement. "In the normal course of events, digging an ocean would be an impossibly huge project. Way beyond the capacity of Inferno's engineers. Of anyone's engineers. But all of a sudden someone dealt us a wild card."

"Go on," Caliban said.

Fiyle leaned forward in his chair, and went on in an earnest tone of voice. "There's a guy by the name of Davlo Lentrall. He was working on something called Operation Snowball. A small-scale, low-budget project that's been running for a few years now. You find comets in suitable orbits, set mining machines and robots on them, and, quite literally, set the robots to work making snowballs, mining hunks of ice. You load the snowballs into a linear accelerator that fires them toward the planet, one after another, over and over, working nonstop, around the clock. You fire the snowballs toward Inferno, one after another, over and over and over again, millions of them, until the whole mass of the comet is delivered to the planet in five- or ten-kilo chunks.

"Each snowball vaporizes as it enters Inferno's atmosphere-and there's another five or ten kilos worth of water vapor in the atmosphere. Repeat five or ten or twenty million times, and you'll got a substantial increase in the amount of water on the planet. Some of the water escapes to space, and some of what's in the comet isn't water-but the other elements serve as nutrients, and we can use those too. Every little bit helps-that's the Operation Snowball motto. They've chewed up nine or ten small comets that way in the last few years."

"I have heard of the project, and seen the constant streams of meteors that sometimes appear in one part of the sky or another. What of it?"

"Lentrall found Comet Grieg while he was doing a scan for comets suitable for Snowball. Except Grieg wasn't suitable for Operation Snowball. It had too little water ice, and too much stony material. And that should have been the end of it-except for two things.

"The first thing was that Lentrall saw how close the comet was going to come to Inferno. The second thing was that Lentrall was-and is-an arrogant, ambitious little man who wanted to be a big man. He was sick and tired of pushing numbers around for Operation Snowball. He was looking for a way out, a way up. Something big. And he found it."

"And what, exactly, was that something big?"

"Deliberately dropping a comet on the planet in order to dig that polar sea and its outlets," said Fiyle. "And who cares if the New Law robots get in the way?"

A human would have professed shock and refused to believe such a thing could be. But Caliban was not a human, and he had never suffered from the human need to try and reshape reality by denying the unpleasant parts of it could exist. Instead he moved on to the next logical question. But, even as he asked it, somehow he already knew what the answer had to be. "You refer to the New Law robots being in the way. Assuming they do drop a comet on the planet-where, precisely, do they intend to drop it?" he asked.

"On the Utopia region," Fiyle said. "And if it's anywhere near where I think it is, your hidden city of Valhalla is right in the middle of ground zero."

SOPHON-06 WATCHED PLACIDLY as Gubber Anshaw unplugged the test meter from his diagnostic socket.

"That will do for this trip," Gubber said cheerfully.

"Do I still register as sane on all of your meters, Dr. Anshaw?" asked Sophon-06.

"So far as I can tell," Gubber replied. "I have yet to work out what, exactly, should be defined as sanity among New Law robots."

"I thought the majority was always sane," Lancon-03 suggested from across the room.

The human shook his head as he put away his equipment. "I don't believe that is true for my species," he said. "At least I hope it isn't. As for your species, I am still at the beginning of my studies. I've done tests on dozens of the New Law robots in Valhalla. The vast majority of the New Law robots seem to fall within a narrow band of personality types. You are a careful, earnest, thoughtful group. The world, the universe, is a very new place to you, and you seek to explore yourselves and it at the same time. You want to know where you belong."

"And you see that as the primary motivation for New Law behavior?" asked Sophon-06.

Gubber thought for a moment. "There is a very ancient procedure used by humans to examine their own drives and impulses. It has gone under many names, indeed many disguises, as the millennia have passed. But the basics are always the same. The subject is required to speak to a listener, but it is not what the listener hears that matters. What is important is that the subject is forced to order his or her thoughts and express them coherently. In the act of speaking to the listener, the subject speaks to himself or herself, and thus is able to perform a self-examination."

"In other words, it does not matter what you think our basic drives are," said Sophon-06. "What is important is that we take the opportunity to ask that question of ourselves, in the most objective way possible."

"It is useful to ask the question," said Gubber. "But it is also important to express the answer."

"Or at least an answer," said Lancon-03. "So come, friend Sophon. Tell us. What is it that you think drives the New Law robots?"

Sophon sat motionless, deep in thought. "It is certainly a question that goes to the center of things," he said at last. "Why do we hide away here in Valhalla, obsessed with secrecy? Why do we seek to develop our own aesthetic, our own way of looking at the world? Why are we driven to improve and demonstrate our skills as terraformers? I think all of these can be explained by our desire to survive. We hide to avoid destruction, we seek acts of creation to develop a system of reference for the greater universe, and we sharpen our skills to insure that we are of more use alive than dead."

Gubber considered Sophon-06 thoughtfully. A coldblooded, even brutal, analysis, but cogent for all of that. It came closer to the truth than most theories did. "It has been interesting, as always," he said, preparing to take his leave. "I look forward to my next visit."

Lancon-03 nodded thoughtfully, mimicking the human gesture. "I am glad to hear it," she said. "I hope we are still here when the time for that visit comes."

GUBBER HAD MADE the trip from Valhalla often enough to take all of the journey's odd features for granted. One never came in or went out by the same route, and one rode in a different sort of sealed and windowless vehicle each time one arrived or departed. Nor did one journey to or from Depot ever take anything like the same amount of time as the one before it or the one after. As Sophon-06 had observed, the New Law robots invested a great deal of effort in order to stay hidden. Gubber therefore paid no attention to the journey back and forth to Depot. He had something else on his mind: the question of New Law robot sanity.

Well, what was sanity, anyway? Surely it was something more than the will of the majority. He had never given much thought to defining the term. It was simply one of those concepts that were hard to define, and yet easy to recognize. One could say with a high degree of assurance that a given being was sane, even if one could not define the term.

And, of course, the converse was true. Which was why Gubber Anshaw always preferred to time his visits to Valhalla for times when Prospero was not there. Not that it was always possible to do so. Gubber had simply been lucky this time.

He did not like Prospero. He did not like dealing with Prospero. The other New Law robots were thoughtful, careful, reticent beings. Prospero was none of those things.

And, if one defined the other New Law robots as sane, Gubber Anshaw was far from certain that Prospero was that, either.