“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.