"Over here!" yelled an unhappy rebel. "I'll do anything!" The Historian ignored everyone but Mihalik and Cheryl.

"Don't let him get to you, Frank," she urged. "He's just trying to use psychology."

"Psychology wouldn't touch him," said the Historian, smiling wickedly. "I've seen dead flounders with more on the ball than he has."

"All right," said Mihalik evenly, "go ahead and gloat. You're mighty and powerful and you've got us at a disadvantage. Now what?" "You're 'disadvantaged' right up to your heroic armpits." The Historian shrugged. "So here's the deal: I want you to worship me."

"Okay," said Mihalik.

That startled the Historian. "You will?" he asked, suspecting some clever subterfuge.

"Sure," said Mihalik. He didn't even know what "subterfuge" meant.

"If I send you back to your universe, will you still worship me?"

"If you want."

"I can check, you know. I can whip you right back into this glacier if you try any funny stuff."

Mihalik tried shrugging, but he couldn't move a muscle. "I know when I'm licked," he said.

"Frank!" cried Cheryl. "What are you saying? You--"

"Shut up, Cheryl," said Mihalik. He'd never said that to her before.

"And I want everybody else in your universe to worship me, too," said the Historian. "You'll be my prophet."

"Sounds fine," said Mihalik. "What happens to me when I die?"

"Oh, you won't die. You'll ascend bodily into the 1939 World's Fair."

"How could anybody ask for more than that? You're on."

"Frank!" screamed Cheryl.

"Shut up, Cheryl," said the Historian. "Frank, you won't regret this. You'll have all sorts of special privileges, too; I'm very generous that way. I'll get you out of this ice now -- just you. It will take only a couple of minutes."

"Take your time," said Mihalik, "I'm not busy." The Historian walked cautiously back across the frozen lake.

"You cruddy traitor!" yelled one of the rebels. All the other Underground members joined in shouting insults and curses; even Cheryl wept bitterly. It meant nothing to Mihalik; he was made of stern stuff.

A few moments later, just as promised, Mihalik was standing in the Historian's parlor; he was normal size and dressed in a fresh Agency uniform. Cheryl had not come with him. The Historian regarded him warily. "No tricks now," he said. "Remember what I can do to you. Remember what I can do to your girlfriend."

"You don't have to rub it in," said Mihalik grumpily. "I'm a tough compet.i.tor and a fierce fighter, but I'm not an idiot. I can size up a lost cause when I see one."

"Good. Now, let's hear a little sample worshipping."

"Thank you, O Historian, for releasing me from the dreadful lake of ice."

The Historian frowned. "That was terrible, but I guess you'll get better with practice. Well, you know the rules -- one golden calf or anything like that, and it's back to Popsicle City. Got it?"

"To hear is to obey."

"That's better." The Historian came toward Mihalik with a couple of sheets of paper in his hand. "I didn't bother with clay tablets," he said. "I made a kind of preliminary list of commandments here that I want you to take a look at. There are seventy-six of them so far. Now we'll be having a test on this material tomorrow, so I want you to--"

Mihalik took the pages with one hand and slipped his right foot behind the Historian's. He jabbed hard at the man's nose with the heel of his other hand and yanked the Historian's leg out from under him at the same time. The Historian hit the floor hard, and Mihalik dropped beside him instantly. "I have my fingers on this pressure point in your throat," Mihalik said in an ugly low tone. "I have my other hand on the opposite point. Now do you know what happens if I press real hard on both of them at the same time?" The Historian's eyes were wide with fear. "You go to sleep," said Mihalik. "Your brain gets no blood. If I press for a little while, you'll wake up feeling real bad. If I press too long, you won't wake up at all. Now we're ready to negotiate."

"Uh huh," said the Historian in a squeaky voice.

"I want Cheryl with me."

"Uh huh." His nose was broken and b.l.o.o.d.y, and he was struggling to breathe. "I want you to send us to our correct universes."

"Uh huh."

"Do whatever you want with these fools here, but leave our universes alone from now on."

"Uh huh."

"How do I know I can trust you?"

The Historian just stared. They had come to the inescapable fine print in the contract: there was no way that Mihalik could keep the Historian from pulling some kind of trick once the Historian got his hands on his equipment again.

"I may be mad, as you said," squeaked the Historian. "I may be ambitious and hungry for power and all of that, too; but I'm still an honorable man. We're all honorable men, Frank. Shakespeare said that."

Mihalik thought about that for a moment, but he didn't loosen his hold on the Historian's throat.

"Frank?" said another voice curiously.

Mihalik looked up. Standing in the doorway, wearing a white lab coat and looking bewildered, was Ray, good old Ray, the best backup man in the business. "Where you at, Ray?" said Mihalik. He took his fingers off the Historian's neck, clasped his hands together, and brought them down as hard as he could on the terrified man's larynx. The Historian gave a strangled scream, took a few difficult, rattling breaths, and died.

"You killed him, Frank."

"Had to, Ray. Did you come to take me home?"

"No, 'fraid not," said Ray, staring at the contorted corpse on the carpeted floor. "I came to tell you why you're stuck here. Why we're stuck here, now."

"Oh." Mihalik began to wonder if possibly he'd been a little premature in his dispatching of the Historian.

"We need energy, Frank, lots of it. We're marooned here because of something called 'temporal--'"

"'--inertia.' I know. Cheryl told me all about it before." Ray looked around the room. "Where is she?"

Mihalik stood up and took a deep breath. "Frozen into an ocean of ice, but it's all right: she wasn't the real Cheryl, anyway."

"Oh, that's okay then, I suppose," said Ray. "Now, see, we need this huge amount of force from this side to unstick you, and then they'll be able to draw us right back to our world."

"We tried that a long time ago. It didn't work."

"You didn't use enough force," said Ray.

"How big a force are you talking about?" asked Mihalik.

Ray dug in a pocket and pulled out a sc.r.a.p of paper. He handed it to Mihalik. "A whole h.e.l.l of a lot,"

he said.

Mihalik read the note; it was written in the familiar scrawl of Dr. Waters: Hi, Frank, how's the boy?

Slight hitch -- need your co-operation if we're ever going to see your foolish mug around here again, not to mention Cheryl and Ray. Vital that you subject yourselves to great force, a minimum of 5 x 10^42 newtons. Ray will be briefed; so if anything happens to Ray, you're finished. Regards to all. See you soon unless you screw up. Your friend, Bertram A. Waters, Proj. Dir.

Mihalik read the note through a second time. "It still doesn't mean anything to me," he said.

"I know," said Ray, "that's why he briefed me. See, the force we have to get hit with is really huge.

You're not to worry, though, because almost everything has been taken care of. Or it should have been, a long time ago."

"Almost everything? And 5 x 10^42 newtons? What in G.o.d's name is a newton?"

"Oh, a newton is equal to exactly one hundred thousand dynes. They're units of force. It takes one newton to accelerate one kilogram one meter per second per second."

"Uh huh. That would be a little tap on the wrist. Now the big number--"

"What we get pounded with, you mean."

"--is roughly how much force? Give it to me in terms I can understand." Ray smiled. "That's easy, Frank. There's never been a force like that in the whole history of the world.

Dr. Waters calculated that the only way we could shoot back home is if we stand under the moon when it crashes into the Earth."

"What?"

Ray patted the air soothingly. "Now, I know it sounds risky--"

"When the MOON crashes into the EARTH?"

"There's no other way, Frank. And Dr. Waters's calculations even leave a little room for error. See, the ma.s.s of the moon is about 7.35 x 10^22 kilograms, and its...o...b..tal velocity, on the average, is 1.33 x 10^10 meters per second. You end up with a collision of a pretty hefty 6.5 x 10^42 newtons, which as you can see is a safety factor of 1.5 x 10^42 newtons, any way you look at it."

"Safety factor!" shrieked Mihalik. "With the moon falling down out of s.p.a.ce onto our heads, you're talking about how nice that it's going to hit a little harder than you figured? We won't even be jam, Ray.

We won't even be a damp stain. The whole world is going to feel it, buddy, and whoever happens to be hanging around underneath while the moon falls those last couple of miles, well, they'll be lucky to have two electrons to rub together when it's all over."

"This is all a.s.suming that the people in the past -- in the past from the viewpoint of here, in the future from our own time, I mean -- took care of binding up the moon for us."

Mihalik laughed; he was actually delighted. He'd never heard such intense nonsense before, and he'd listened to a lot of it since that high noon in 1996 when he let Dr. Waters bathe him in that amber ray.

This was the best nonsense yet. "Bind up the moon?" he asked. He felt a gentle curiosity; he hoped Ray had been briefed on that, too.

"Oh, sure," said his eager backup man. They were still standing around awkwardly over the dead body of the Historian. Mihalik gestured toward the armchairs, and they seated themselves. "See," Ray continued, "there's this thing called Roche's limit."

"Roche's limit. Okay."

"Now Roche's limit says that if a body is being pulled in toward another body, like the moon toward the Earth, at a certain distance depending on their relative ma.s.ses and one thing and another, there will be these terrific tidal forces that will rip and tear at them and pull them apart and shred them down into puny little rocks and stones. That's what's going to happen to the moon, see? It will end up just rocks and stones in orbit around the Earth, like the rings around the outer planets. Roche's limit is where Old Luna goes blooie, doing you and me no good at all, except that these wonderful engineers who lived maybe seven hundred thousand years ago from here were supposed to wrap the moon up in something so that it would all hold together."

"Why would they do that?" asked Mihalik. "I think rings around the world would be less traumatic than the whole moon blamming into us broadside."

"They did it as a favor to Dr. Waters," said Ray.

"Oh," said Mihalik. "What did they use?"

"Well, see, I'm not sure they actually accomplished it because I left before Dr. Waters came back from the future to ask them to do it. I think he suggested Dutch tape."

"You mean duck tape, Ray."

"I don't know. Dr. Waters, he's the smart one. He figured in all the angles, pal, let me tell you. Did you know that the Earth has been slowing down on account of the pull of the moon? Ever since the beginning, I guess. And if the Earth slows down, the loss of angular momentum has to be taken up somewhere else in the system -- by the moon, that is. So the moon speeds up a little and escapes a little farther away. Now this gets tricky but kind of neat the way it all works out and all: way far up in the future -- where we have to go -- a normal day will last more than thirty-six hours because the Earth will have slowed down so much. After a certain point, the moon will be far enough away that it won't be having as big an effect on the Earth, and the process will start to reverse; the Earth will reel the moon in like a gasping trout. That's when all the special effects start to go off: volcanoes, earthquakes, all that end-of-the-world stuff. The moon will be so close to the Earth, see, it will be whipping around in orbit injust two hours, instead of a month. It will be so close you could almost hit it with a slingshot. The Earth will regain momentum and start spinning faster and faster. Continents will fracture and sink, tidal waves will slosh over everything, it will be just awful. Right about then, that's when the moon hits Roche's limit.

That's when the whole ball of wax hits the fan. You and I will be waiting around to see what happens; if we're lucky, the duck tape will hold and the moon will go blammo into our tired old world. If the moon shatters into fairy dust, well, we'll be the first and the last to know about it. How's that for something to look forward to, Frank? Did you have any idea when you volunteered to go back in time that you'd end up at the end of the world, waiting for the G.o.dd.a.m.n moon to come screaming down on your head like the Flyswatter of the G.o.ds?"

Mihalik had listened to this somewhat overwrought speech with his eyes closed, fighting down nausea.

"I just want to go home," he said. "I just want to wake up in the morning and be home. Maybe it's all a dream, Ray. Maybe--"

"We have work to do," said his faithful companion. "We have to get ourselves to the last days of the world as we know it."

Mihalik opened his eyes. The dead body of the Historian was right where it had been; the World's Fair and the everlasting fields of flowers were still out beyond the boarded-up windows; Frank heard the locking of little stones. .h.i.tting the wood, just as the Historian had claimed. At this moment, Mihalik regretted his violence. He didn't want to go with Ray to the end of the world; he'd rather take his chances with Cheryl in the lake of ice, slaves of an insane despot.

It was too late, though. It was too late. Mihalik had acted, he had made his choice, and now he had to see it through to the conclusion. His gaze fell on a framed quotation by the Historian's desk (so like the framed quotations Dr. Waters always tacked up everywhere): "Can a man kill time without doing injury to eternity?" It was attributed to somebody named Th.o.r.eau. Whoever he had been, he'd hit the nail right on the head.

The image of a hammer pounding a nail made Mihalik wince -- he was going to be the nail, and the hammer was going to be the hurtling moon of destruction.

...and Your Little Dog, Too!

They left the Agency Building and wandered out into the Fair. Mihalik forgot for a moment that Ray had not actually seen the Fair before, so he pointed out a few of the more interesting sights. "I know what those are," said Ray, bouncy as a child, hurrying toward the thematic white sphere and pyramid. "The Pylon and the Terrasphere."

"The Trylon and Perisphere," Mihalik corrected.

Ray turned suddenly. "Frank," he said, "I know you're a hero, a better hero than I could ever hope to be, though we've had all the same training and I'm younger and stronger than you. I have to remind you, though, that I did much better on my English College Boards. I know what a 'pylon' is, and even 'terrasphere' makes slightly redundant sense, but there just aren't any such words as 'trylon' and 'perisphere.'"

Mihalik smiled. "Ray, one thing you're going to have to get used to about the past and the future: n.o.body ever does anything for a good reason. History only pretends that they did."

Ray blinked his big solemn eyes and nodded. "Where are all the people, Frank? The Historian's defeated, the battle's over. Where is everybody?" Ray turned and looked first down one avenue, then down another. "Come out, come out, wherever you are, and meet the young hero who fell from a star."

Mihalik grunted and grabbed Ray's arm. "Why the h.e.l.l did you say that?" he asked.

Ray looked puzzled. "I don't know. Why? Did I say something wrong?"

"I just didn't expect you to show up here quoting The Wizard of Oz, too, just like all the unreal people in the unreal universes."

"Did I make a quote? I didn't realize it."