“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.”