Alvar Kresh had ordered him to layoff the investigation of the Government Tower Plaza incident, but there were some cases so big you couldn’t ignore them even if you tried. Three separate suspects picked up on other charges had volunteered credible information about that attack, all of it pointing straight for the Settlers. Maybe Tonya Welton’s people were making another try to stop the comet. Maybe out of genuine fear and concern, or maybe because they wanted to maintain their dominant position on the planet. According to the watcher reports Justen got, Cinta Melloy had been spending a lot of time in Depot, enough that Justen had started to wonder why. Maybe now he had his explanation.

It could have been the Ironheads themselves, or some offshoot of them, either truly kidnapping Beddle as part of some complex power play, or else staging the kidnapping with the cooperation of Beddle for some intricate reason that was not yet clear. It had been in the back of Justen’s mind to consult with Gildern about the kidnapping at once, but a contrary idea was forming at the back of his mind. Best to leave Gildern alone. Maybe not even inform him of Beddle being snatched. More than likely, they would only be able to keep the lid on the story for a few hours, but even might be enough. If Gildern did have guilty knowledge, he might well slip up in some way. Best to have a watch put on him at once.

It could be that Davlo Lentrall’s terrified and belated regrets over what he had done had led him to an act of desperation. The old Lentrall could have done this job-everything at the crime scene had been done with a scientist’s methodical care. But would the new Lentrall, traumatized by the Government Tower attempt to kidnap him, the death of his robot, and the notion of his own guilt, be stable and rational enough to manage it? But if an unbalanced Lentrall had done it, then the symmetry of the kidnap victim turning kidnapper had its own weird revenge-logic. Had Lentrall ever said anything to suggest he blamed the Ironheads for the attack on him? The investigation would have to check into that.

Or, of course, it could have been anyone with the quite understandable motive of not wanting comets dropped on themselves. The Comet Grieg project had generated a lot of opposition among the populace of Inferno, especially in the Depot area. And Beddle had come out in favor of the comet plan.

Except-Wait a moment. Consider the ransom demands. Stop the comet and five hundred thousand in Trader Demand Credits. A political and a financial demand. Justen did not know a great deal about kidnappers, but he did know that those two demands didn’t go together. It seemed to him that the sort of person who would perform this kidnapping out of some misguided and heroic desire to save the planet would not be the sort to care about money. Conversely, the sort who would do it for mercenary reasons was not likely to be much interested in altruistic acts. The demands did not hold together.

Put that to one side for a moment. Names. Think about the names. There was something at the back of his mind. Something linked all the names together. Lentrall. Gildern. The Settlers. The Ironheads. Someone or something that

And then he had it. He had it. There was one person with links to them all. And he knew who he was going to pull in first.

He looked out the window, and saw to his surprise that they were coming in on final approach to Depot. Good. They could get started right away.

He would be very surprised indeed if Norlan Fiyle didn’t have something to tell him about all this. He would send out an arrest team at once.

And while they were pulling him in, Justen was going to inform Kresh about the kidnapper’s two demands. He wasn’t going to be able to get the comet stopped, but there might just be something he could do about that ransom. He was starting to get an idea.

“DO WHAT YOU like about the ransom,” Kresh said to the image on the comm center screen on his office. “We can afford to front the money, if need be. And I agree it could do no harm to keep Gildern in the dark. But that comet is on course, and we’re not going to change that.”

“Understood, sir,” Devray replied. “Thank you for the authorization. I’ll keep you informed. Devray out.” The screen went dead.

“How long now, Donald?” Kresh asked.

“Initial impact of Comet Grieg is projected to occur in four days, eighteen hours, fifteen minutes and nine seconds. Sir, concerning the rescue of Simcor Beddle, I believe it would be wise if I were to go to the scene and-”

“Donald.” Fredda’s voice was flat and hard. “You are to leave the room at once. Go to the library and wait. Do not return, and do not take any further action of any kind until called for.”

Donald turned toward Fredda and looked at her for a full ten seconds before he responded. “Yes, ma’am. Of course.” He turned and left the room.

“First Law makes him want to save Beddle, in spite of Devray and his team being on the scene. I suppose we should have been expecting that,” Kresh said.

“I have been expecting it,” said Fredda. “Comet Grieg all by itself is enough to set off significant First Law stress in any robot. An event as big and violent as that, with so many chances for danger to humans, would have to set off First Law stress. The only way a robot could deal with that sort of thing at all would be to be active, to do something, to be part of the effort to protect humans from harm. Donald has been part of that effort. It’s why he’s been able to hold together as well as he has. It helped that the threat up until now has been generalized, unfocused. Something somewhere would probably go wrong somewhere to harm a human. Generalized preventive action was enough to balance that. The general and collective robot effort was enough to meet the general and collective threat.”

“But now it is all different,” Kresh said.

“Now it’s different,” Fredda agreed. “Now there is a specific and extreme threat against a known individual. Normally that would not be enough to cause a First Law crisis. A robot on this side of the world would know that the robots on that side of the world would do all that could be done. But with the overarching stress of the Comet Grieg impact on the one side, along with the high probability that Beddle is somewhere in the impact area-that combination of overlapping First Law stresses could force any robot into action.”

“What do you mean by action?” Kresh asked.

“Anything. Everything. I couldn’t even begin to sort out all the permutations between now and the impact. But the basic point is that Beddle’s disappearance could create a tremendous First Law crisis for every robot on the planet. If Beddle is indeed in the impact area-or even if there is merely reason to believe he might be-then any robot made aware of his circumstances will, in theory, be required to go to his rescue, or to work in some other way to save him-perhaps by trying to prevent the comet impact. Suppose some team of robots grabbed a spacecraft and headed for Grieg to try and destroy the comet? Of course, higher-function robots will understand that an attempt to prevent the comet’s impact might wreck hopes for reviving the planet’s ecology. That would almost certainly result in harm to any number of human beings, many of them not yet even born.

“Then there is the impossibility of proving a negative. Even with the best scanning system in the universe, unless Beddle walks out somehow, there can be no way of being absolutely sure he is not still in the impact area, or the danger zone surrounding it. It is therefore, at least in theory, possible that he is actually safe. If so, then working to save Beddle is wasted effort, and could actually cause danger to other nearby humans by preventing attention to their evacuation. It is just the sort of First Law crisis that could tie a robot in knots, even to the point of inducing permanent damage.