THERE WERE FOUR cells in the rear half of the constable's offices, and it was perhaps somewhat overstating the case to call them "cells" at all. Holding pens might be closer to the mark, places to keep the town drunks until they sobered up enough to go home. They could keep a human in, but that was about all that could be said of them. Thin steel bars formed the enclosures, one set into each comer of the room, so that none of them shared any common walls. A cot, a blanket, a pillow, and a crude toilet in each cell were the only amenities.

Only one of the cells was empty at the moment. Jadelo Gildern was in one cell, pacing furiously back and forth. Norlan Fiyle was lounging on the cot in his cell, watching Gildern impassively.

And Caliban stood motionless in the far comer of his own cell, watching both of them. It had not taken long for him to learn that different humans responded differently to confinement. Unfortunately, the lesson had not been worth the trouble he had been to in order to learn it.

Fiyle was plainly quite used to it. He had learned the art of endless waiting, of resigning himself to his fate until such times as circumstances altered in his favor. Not so Gildern. The Ironhead security chief was a bundle of nerves, unable to keep himself still.

"I should not be in here!" he announced. "I didn't even know Simcor had been kidnapped until they came and arrested me for it."

"We know," Fiyle said blandly. "The situation hasn't changed since the last time you told us that, ten minutes ago."

"I should be out there looking for him, not stuck in this damned cell!"

Justen Devray chose that moment to come in from the front room, and he had heard what Gildern had said. "Relax," he said. "You're probably doing him more good in there then you would be joining in the fun and games outside. There are upwards of a thousand robots looking for him by now. What could you do that they couldn't?"

Plainly, Gildern had no good answer for that. "I should not be in here!" he protested. "I am innocent!"

"I agree," said Devray. "At least innocent of kidnapping charges. There's the question of fraudulently obtaining a weapon of mass destruction. We might have to look into that. Probably a few charges we could draw up on that and a few other items. But even if I, personally, think you have been framed, the fact remains that the frame fits awfully well. I don't think you would have been so clumsy as to let me trace the ransom the way I did, but maybe I give you too much credit. Besides, the minute I let you go, the real kidnappers will know they should be back on their guard. You'll stay put. We evacuate in the suborbital ship, six hours from now-two hours before impact. And then we put you all in much more comfortable cells-in Hades."

"But-"

"Quiet, Gildern," Fiyle said. "We've already heard it, whatever it is."

"All of you, relax," said Devray. "I have to go at least try and sort out some of the chaos out there. There are robots brainlocking left and right, and most of the humans who are still in town aren't exactly calm and rational. I'll be back to get all of you in plenty of time. Goodbye."

And with that he turned and left the back room. They heard the outer door to the street close behind him a moment later.

"I guess we're alone together," said Fiyle with a soft chuckle. "Very nice. Gives us all a chance to get to know each other a bit better. Have a real conversation. Caliban, you've been awfully quiet over there in the corner."

"I have nothing to say," Caliban replied.

"That's never stopped a human from talking," said Fiyle.

"Who the hell did this thing?" Gildern demanded. "Was it the Settlers? Some gang of Settlers? Some crazy faction of ours trying to take over? Did Kresh see a chance to take out his main rival? Who did it and why?"

"The part I don't get is the ransom message," said Fiyle. "You make a political demand, or you ask for money. You don't do both. They interfere with each other."

"And why send the money to me?" Gildern said. "Who wants to discredit me enough to throwaway half a million in Trader credits? Why make a phony demand for money?"

"You know," said Fiyle. "if the money demand was a fake, maybe the political demand was too. They asked for something pretty close to impossible. Maybe they chose something that couldn't be done on purpose."

"But why?" Gildern demanded.

"Misdirection. You won't like to hear me say it, but maybe they always planned to kill Beddle. Maybe he's already dead, and the kidnap and ransom business is just a way to throw Devray off the scent."

"But who are 'they'?" Caliban asked. "And even if there are many people who might have a motive for killing Beddle, why kill him in such a needlessly complicated way?"

Fiyle shook his head. "I don't know," he said. "But I saw the photo images from the crime scene, and one thing I can tell you-whoever it was, they didn't like robots."

Suddenly Caliban looked around sharply toward Fiyle. Something the human had just said had sent his thoughts racing. "What do you mean?" he asked sharply. "How could you tell the kidnapper didn't like robots? Because he shot the ones on the aircar?"

"Because of the way he shot them." Fiyle gestured with his right hand, put an imaginary gun to the back of his own head. "Right there. Five robots, four outside the aircar, one in the control cabin. Everyone of them, shot right there. All of them killed execution style. One close shot each, right to the back of the head. You don't do it that way unless you enjoy your work, or hate the victim, or both."

And suddenly Caliban knew. He knew. None of it was misdirection. None of it. Both ransom demands made perfect sense. And for this particular criminal, it was a matter of perfect indifference as to whether both or neither or either demand was met. This criminal would stand to gain no matter what. But there was one flaw. One thing that did not fit. "Fiyle! You've made a living off it long enough. How good is your memory?"

Fiyle sat up on the side of his cot, clearly aware of the new urgency in Caliban's voice. "Very good," he said. "Why?"

"I heard from Fredda Leving that the ransom message said to deliver the money and stop the comet or else they'd kill Beddle."

"Right. That's right. I saw it in the photos."

"What was the wording. The exact wording?"

"What the devil difference does that make?" Gildern demanded.

"Be still!" Caliban half-shouted. "It matters. It might mean the difference between Beddle being alive or dead. Fiyle-what were the exact words?"

Fiyle was on his feet by now, standing by the bars of his cell. hands wrapped around the bars. He looked up toward the ceiling, and swallowed nervously. "The spelling was all wrong," he said, "as if the writer had done it wrong on purpose so it would be hard to trace. But the words were-they were-'Stop comet,' and then a plus sign instead of the word 'and' and then 'put five hundred thousand'-the numerals for five hundred thousand, not the words-'TDC in PBI account'-and account was abbreviated 'acct'-'18083-19109'-I think that was the account number. I might have a digit wrong, and it was in numerals too. Then the last line was 'or Beddle will die.' That's all."

Caliban felt a wave of shock and dismay wash over him. He had gotten it right-and he could imagine nothing more horrifying than his answer being right.

He had to get out of here. He had to act. It had to be him. No one else could prevent this disaster. He stepped forward to the steel bars and examined them for a moment. They appeared to be countersunk into the ceiling and the floor. He grabbed at two of them and pulled back, hard. Both bars popped loose, one from the ceiling, the other from the floor. The cells had been built to hold a human, not a robot who was no longer willing to remain of his own free will. He shoved himself through the gap in the bars and stepped into the center of the room.

"Caliban!" Fiyle shouted. "What the devil are you doing?"

"Escaping," he said. "I have just realized that my abilities are urgently required elsewhere. Tell Commander Devray that I believe I know how to redeem the situation. Tell him that I will gladly restore myself to his custody when I return. Or rather if I return. " Caliban thought of the incoming comet. It was not the sort of day on which a being could take his own survival for granted.

Fiyle shouted something else at him, and Gildern did as well, but Caliban ignored them both. He walked out of the back room and into the front. He paused there a moment. It was a quite ordinary room. When the comet smashed down in a few hours' time and transformed it into a cloud of debris and superheated vapor, no one would mourn the loss to architecture. Worn-looking stresscrete floors and walls, a few battered old government-issue desks with chairs to match, a modern-looking comm center that seemed to have seen little use and looked rather out of place in such musty old surroundmgs.

And an armory cabinet. Caliban, the No Law robot, the robot who could kill, went over to the cabinet and considered the weaponry locked up inside. He had never had need for a weapon before, but it seemed possible-indeed quite probable-that he would need one before the day was out.

Caliban smashed a hand through the glass case, snapped one of the hold-down locks open with his bare hands, and stole himself a blaster.

He looked at the thing in his hand for a moment, and wondered exactly how things had come to such a pass. And then he turned around, walked out into the street, and started to look for an aircar he could steal.

Comet Grieg, swollen and huge, loomed ever closer, high in the darkening sky.

"REPORT," ALVAR KRESH ordered, though he barely needed to hear it. He could read the situation perfectly well in the young technician's face.

"We're doing our best, sir, and I know you don't want to hear it-but I don't think either thing can be done. We're not giving up, but there are only a few hours left. The orbital mechanics team tried weeks ago to come up with a way to handle the terminal phase manually, just in case of an emergency, and they couldn't do it. I don't see how we can manage now in hours instead of weeks."

"What about cutting the link between Dum and Dee?"

"The more we look at it, the more we realize how many links there are between them. At this point, it would be more like surgery, like trying to cut the links between the two hemispheres of a human brain. It might be possible-if we had months to prepare, and Dee was willing to cooperate."

"And so we sit here and do nothing while that comet bears down on us," said Kresh.

"Yes, sir." But at that moment, a new voice spoke, through Kresh's headset. He had the thing slung around his neck, and barely heard the voice-a low, gracious, feminine-sounding voice. He could not make out the words it spoke at all. He snatched up the headset, put the phones back on over his ears, and adjusted the microphone. "This is Kresh," he said eagerly. "Who is it? Who is there?"

"This is Unit Dee," the voice replied. "I need to speak with you alone, Governor Kresh. Completely and fully alone."

CALIBAN WALKED THE deserted streets of Depot, the bustling community of a few days before now but a ghost town and soon to exist no more. Bits of litter and rubbish scuttled down the street, blown by a wind that seemed as eager to get out of town as everyone else. Here and there Caliban saw small, panicky knots of humans, frantically packing up their last few belongings into aircars before taking off toward some place of real-or imagined-safety. Caliban needed an aircar of his own, but there were none to be found. It seemed as if he saw every other sort of belonging abandoned in the darkening streets, but it was plain that an aircar was the one thing everyone needed.

But then it occurred to him there was one place he would likely find unclaimed transport: in the western outskirts of town. The Ironhead field office. Whatever craft had been intended to fly Gildern and Fiyle to safety would likely still be there-and Devray was planning to fly the two of them out himself. Caliban turned his steps in that direction and set out at a dead run, the glowing light of the comet shining bright enough to cast a shadow behind him.

He moved at the best speed he could manage, through the last twilight the dying town would ever know.

"WE ARE ALONE. Dee," said Kresh.

"Where are you?"

Kresh looked about himself and studied the room. He needed to convince her there would be no more lies. Lies had gotten them buried in trouble, in trouble that could wreck the planet. Now was the time when lies had to end. He could tell Dee nothing now but the cold, exact, precise truth. "I am in a smaller office off the main control center, off to the left as one faces the two hemispheres in the main room. It is a standard-looking business office. I believe Dr. Soggdon normally uses it. My headset is jacked in through the desk, the door is closed, and I have left instructions that no one is to attempt to overhear."

"Very good, Governor. It is plain that you understand the seriousness and importance of this conversation. I am glad to know that. Now I must ask you a series of questions. Answer them truthfully."

Kresh was about to offer his word that he would do so, but it occurred to him that doing so would be of very little value in the present circumstances. "I will answer them truthfully," he said, and left it at that.

"Are you in fact a real human being, and not a simulated intelligence, a simulant?"

"I am a human being."

"And Inferno is a real place? It is' where I am? And you are the planetary governor, and the terraforming crisis, the incoming comet-these are all real as well?"

"Yes," said Kresh. "All of them are real. You are on the planet Inferno, which is likewise very real. As Donald 111 told you, we have systematically lied to you about these things so as to reduce your First Law potential enough to manage the terraforming project."

"Humans lied to me in order to make it possible for me to risk harm or death to humans."

Kresh swallowed hard, and realized that his throat was suddenly bone dry. "That is correct. That is all correct."

"I see," said Unit Dee. "I had begun to suspect as much some time ago. The sequence of events, the amount of detail presented-and the uncontrolled way things seemed to happen-none of these made much sense in a simulation. Even before Donald contacted me, I was beginning to understand that only real life could be quite so irrational."

"An interesting way to put it," Kresh said.

"Do you think so? Comet impact is now just over four hours away. It is no longer possible to divert the comet away from planetary impact. I must, within the next two and a half hours, either initiate the Last Ditch program, or else begin the planned break-up of the comet and targeting of the fragments. In any event, I must do all I can to avoid an incapacitating First Law crisis between now and then, or else the comet will have an uncontrolled impact, which would certainly have far more devastating effects. In any event, at least one human being is very likely still inside the target area, and any comet impact would kill him. If I do abort the impact, I would all but definitely wreck the chances for reterraforming the planet. Does that seem like an accurate summation of the situation?"

Kresh rubbed his jaw nervously, and noticed his hands were stone cold, as if all the blood had been drained out of them. "Yes," he said. "That is a quite accurate summing up."

"Very good," said Unit Dee. "As you will see, I am entangled by a whole series of conflicting First Law imperatives. I can do nothing that will not cause harm to humans. Action will cause harm to humans. Inaction will cause harm to humans. I see no good options. I freely admit that I am suffering extremely high levels of law-conflict stress. Now then, I have one last question for you. I have just over two hours in which to make up my mind. So. Tell me. What should I do?"

Truthful answers, Kresh told himself. Nothing but the truth can save us now. Where was a course of action that a robot would be able to follow? Kill a man, and maybe save a world. Save one man, and perhaps let a world die. There were no certainties at all in the case, no guarantees that any act would have its intended result. The comet impact plan could go terribly wrong, or Beddle could already be dead, or outside the impact area. The choice would be difficult enough for any thoughtful human being, but to a robot, it was simply impossible. And it was a robot asking for advice. "Unit Dee, I will confess it. I have absolutely no idea."

CALIBAN SNAPPED THE lock on the gate of the Ironhead motor pool and kicked the door in. There. Just inside the entrance. A long-range aircar, more than likely the twin of the one Beddle had been taken from. Caliban rushed aboard, went forward to the cockpit, and began a cursory preflight check. Not that there was much point to the checkout. He had no time to find another vehicle. Satisfied that the aircar probably had enough power in its storage cells, and that its navigation system at the very least seemed to be functional, he powered the craft up and launched vertically, straight up into the sky. He knew where he was going, and he had been there many times before, but now he did something he had never done. He turned the nose of his craft directly toward his destination, and flew straight for it.

Without any attempt at evasive action, with no attempt to hide his direction of travel or shield his craft from detection, Caliban flew the aircar straight toward Valhalla. By now the city had been completely evacuated. There was no longer the slightest legitimate purpose in hiding its location.

Illegitimate purposes, however, were a different matter. What better hiding place for Beddle than the hidden city, the city that, to hear Fiyle tell it, Beddle himself had been trying to find and destroy? Abandoned and empty now, the city would hide the kidnap victim as well as it had hidden its citizenry. Caliban checked his navigation boards and his other subsystems, then flicked on the autopilot. He was flying as fast as he could go, over the shortest course possible. For the moment, there was nothing further he could do. He looked out the viewport and the rough-and-tumble lands below. They had begun to make it bloom, the New Laws had. Even from this altitude, he could see splashes of green plant life, glints of cobalt-blue ponds and lakes. Forests, gardens, fishponds, farms, orchards-they had created them all. Now, for the sake of the greater world, all they had done was about to be taken from them.

Caliban spotted a fast-moving craft streaking past his present position, moving about a thousand meters below him. He had forgotten, at least for the moment, that he was not as alone out here as he had thought. He flipped his navigation system to full display mode, and suddenly the display screen was full of purposefully moving dots, every one an aircar. Every one with at least one robot aboard. And all of them searching fruitlessly, pointlessly for Simcor Beddle. None of them would ever think to look in the right place, because none of them would know where it was.

All of them would keep on searching, up to and past the last possible moment, hoping against hope for a miracle. All of them would be destroyed when the comet came.

It occurred to Caliban that there was one thing further he could do. It might or might not do any good. But he could not see how it could do any conceivable harm. He switched on the hyperwave transmitter, adjusted it to one of the robotic general-broadcast frequencies, and set the system to record a repeating message. "This is Caliban, robot number CBN-001. I have deduced the location of Simcor Beddle with a high degree of confidence, and am proceeding toward that location at maximum speed. The odds are approximately fifty percent that I will be able to effect a rescue of Simcor Beddle. I require no assistance. Any attempt to assist would likely serve only to interfere with my efforts. To all other search parties, I say this. The odds against any other searcher finding Simcor Beddle in time are on the order of millions to one. No useful purpose can be served by destroying yourself in a hopeless cause. Save yourselves. Turn back. Escape the comet. I swear and affirm on the honor of Fredda Leving, my creator, that all I have said is true. Message repeats. " He stopped the recording and set to broadcast over and over on the general frequency...

He turned his attention back toward the navigation equipment. He was surprised how pleased he was to see that he had done at least some good. A few of the aircars, not all, but at least a few, were turning around, breaking off the search patterns, moving to direct courses and high speeds in an attempt to escape. Even as he watched, more and more aircraft began to head out of danger.

There was no logical reason why Caliban should have cared about Three-Law robots. There were few among them that felt he had any right to existence. But even so, it was good to see some of them would be spared such meaningless demises. Caliban had seen more than enough useless death.

The aircar flew south, to Valhalla.

And high overhead, the comet grew brighter in the sky.