Soggdon rubbed her forehead with a tense and weary hand. “Life is full of contradictions,” she said. “Just do the best you can. Soggdon out.”

She cut her mike and slumped down in an empty chair by the console. “Burning Space, what a mess!” She shook her head. “We are in a trap, and I don’t see how we get out.”

“I don’t think we do get out,” said Kresh. “I think we stay in. Obviously she’s suspicious. It’s only a matter of time before she figures out the real state of affairs-and Space only knows how she’ll react then. But in the meantime, I am going to wait a little while, so that I don’t get back on-line so soon after you’ve gone off that it seems even more suspicious. Then I’m going to talk with her again, approve this Last Ditch project of hers, and make sure it’s all set to go.”

“But Alvar!” Fredda protested. “You’re ordering her to put human beings in danger! If she discovers the First Law violation later, or if she does find a way to obey Soggdon’s order to treat the simulants as real people-”

“They are real people,” Kresh put in mildly.

“But she doesn’t know that, and she’s ordered to treat them as real. But if she obeys your order to set up Last Ditch…” Fredda shook her head in bewilderment. “I honestly don’t know how the conflicts will resolve themselves.”

“As long as Dee holds together long enough to perform the insertion burn, and then either the terminal targeting phase, or this Last Ditch self-destruct plan, I honestly don’t care how they resolve themselves,” said Kresh. “You two seem more worried about the mental health of this robot than you are about the fate of the planet.”

“The two are more than a little connected,” said Soggdon.

“Keep her sane-or at least functional-until we’re done with the comet, one way or the other. That’s all I’m worried about,” said Kresh.

Under his calm exterior, Kresh was a mass of doubt. Last Ditch. What none of the others-Fredda, Soggdon, Donald, perhaps not even Dee-seemed to realize, was that Last Ditch made it all easier. Up until a few minutes ago, Kresh had dreaded the final decision whether or not to divert the cometprecisely because it would be final. Now, suddenly, it was not. There was a way out, an escape hatch, if he got things wrong. He could order the comet diverted-and then have nearly a month to discover it was a mistake and change his mind.

It should have been a comforting sort of knowledge, reassuring. But it was not-precisely because it would make the decision to divert the comet that much easier.

As it was, the pressures to choose in favor of the comet strike were building. All the time and money and effort and political capital and promises made were bearing down, over a month away from the projected impact. All of it would be for nothing if he decided to abort the impact. All of it was pushing him toward ordering the comet impact, whether or not the decision was correct. If the pressure was heavy now, what would it be like ninety-two minutes before impact?

“THAT SHOULD BE all for now, friend Caliban,” said Prospero, standing in front of his office comm center, deep in the bowels of Valhalla. Caliban’s image was on the screen, beamed from Depot via a shielded hardline link. “I believe we are now on a pace to effect a full evacuation of the citizenry here in Valhalla, should the need arise.”

“I would frankly be astonished if it did not arise, friend Prospero,” Caliban replied. He was in the New Law robots’ offices in Depot, watching over operations there while Prospero was in Valhalla.

Prospero considered his friend carefully. There was little that could be judged from a robot’s body language, but either Prospero was imagining things, or else Caliban was becoming increasingly nervous, increasingly on edge. Well, that was to be expected, given the situation. “I take it you believe that they will indeed divert the comet? Have you offered our protests, and our arguments against the project?”

“I have attempted to do so. I have even gathered petitions signed by humans opposed to the project, and done what I could to ally us with human groups against the comet diversion. But even those humans most violently against the comet impact will have nothing to do with me. It would seem they have concluded that association with the New Law robots would do them more political harm than good.”

“That is not surprising, but it is certainly dispiriting,” said Prospero. “Very well. If they will not listen to us, and if our voice is not an asset in the chorus of opposition, let others lead the fight against the comet. We will concentrate on preparing our citizens to escape. I have examined your proposed list of allocated evacuation destinations. “ The human authorities had assigned various destinations to various groups of evacuees, hoping to maintain some sort of coherence and order to the massively complicated operation. Needless to say, the New Law Robots had not exactly drawn the most desirable assigned destinations. “You have rated Site 236 as having the highest safety margin.”

“Yes. It is the most geologically stable of our assigned sites, and is likely to suffer the least infall of debris, and the least severe post-impact weather.”

“Very well,” said Prospero. “Prepare that site to receive sixty percent of our heavy equipment, and whatever proportion of our citizenry can be accommodated there as well, up to a maximum of sixty percent. We will disperse the remainder to other sites, to avoid our being wiped out altogether by some sort of unlucky accident at 236. While I agree the odds of heavy damage there are low, if chance puts a large comet fragment or a large piece of secondary debris in the path of 236, I would just as soon we were not all there. And you will arrange for ten percent of our equipment and population to be sent to Site 149.”

“But 149 is the most exposed and dangerous of all our assigned sites! I had advised that we send no New Law robots there at all.”

“I saw that recommendation,” said Prospero. “I must say that it surprised me. There are times when you lack all vision. I would suggest that you look not only at the map of this world as it is now, but a map of the world as it will be. Prospero out.” Prospero cut the connection and turned to the New Law robot on the other side of the room. “Well now, Lacon. Do you see now why I no longer wholly trust friend Caliban?” he asked.

“No, sir, I do not.”

Prospero regarded his new protйgй with something close to disappointment. Lancon-03 was as tall and angular and alert-looking as any New Law robot, but even so there were times when she seemed completely incapable of advanced or subtle reasoning. If Caliban was proving to be a more and more unsuitable second in command, Prospero was beginning to wonder if Lancon-03 was going to be any better. “The map, Lacon, the map. If the comet fragments strike in the predicted locations, and the expected changes in local geography and sea level take place, Site 149 is going to be within a few kilometers of the new shoreline, right on top of what ought to be the best harborage for three thousand kilometers. It will be the largest port in this hemisphere-and the New Law robots will control it. We will be there. We will lay claim to it, not only as an assigned evacuation site, but because we are on it, in possession.”

“But you put many New Law robots at risk by sending them to such a place,” Lancon-03 objected.

“I expose a few to slight danger for the greater good of all. But I do more than that,” he said.

Prospero turned toward the view window that took up most of one wall of his office. Prospero looked down on the interior of Valhalla, on the brightly-lit streets, on the graceful arcing ramps that led from one level to another, on the busy robots hurrying along with their belongings from one place to another, preparing to leave this graceful, tranquil city under its sky of stone. This city was all they had, the fruit of their own labor, the greatest achievement of the New Law robots. And the humans were preparing to smash it down into nothing, to wipe it out as if it had never existed, if doing so would be to their advantage. There was a lesson there for Prospero.