"In an infinite number of worlds, anything can happen." He finished that 1 in a whisper. "Everything must happen."

"Chances are one in a duodecillion," said Ching, shrugging.

They arrived at the twisting point then, and, having utilized the freight twist for their vehicle (thus sending it into the Rimbro storage area), they entered the Rimbro probability pattern themselves. First Ching, then Mishnoff.

"A nice house," said Ching, with satisfaction. "Very nice model. Good taste."

"Hear anything?" asked Mishnoff.

"No."

Ching wandered into the garden. "Hey," he yelled. "Rhode Island Reds."

Mishnoff followed, looking up at the glass roof. The sun looked like the sun of a trillion other Earths.

He said absently, "There could be plant life, just starting out. The carbon dioxide might just be starting to drop in concentration. The computer would never know."

"And it would take millions of years for animal life to begin and millions more for it to come out of the sea."

"It doesn't have to follow that pattern."

Ching put an arm about his partner's shoulder. "You brood. Someday, you'll tell me what's really bothering you, instead of just hinting, and we can straighten you out."

Mishnoff shrugged off the encircling arm with an annoyed frown. Ching's tolerance was always hard to bear. He began, "Let's not psychothera-pize-" He broke off, then whispered, "Listen."

There was a distant rumble. Again.

They placed the seismograph in the center of the room and activated the force field that penetrated downward and bound it rigidly to bedrock. They watched the quivering needle record the shocks.

Mishnoff said, "Surface waves only. Very superficial. It's not underground."

Ching looked a little more dismal, "What is it then?"

"I think," said Mishnoff, "we'd better find out." His face was gray with apprehension. "We'll have to set up a seismograph at another point and get a fix on the focus of the disturbance."

"Obviously," said Ching. "I'll go out with the other seismograph. You stay here."

"No," said Mishnoff, with energy. "I'll go out."

Mishnoff felt terrified, but he had no choice. If this were it, he would be prepared. He could get a warning through. Sending out an unsuspecting Ching would be disastrous. Nor could he warn Ching, who would certainly never believe him.

But since Mishnoff was not cast in the heroic mold, he trembled as he got into his oxygen suit and fumbled the disrupter as he tried to dissolve the force field locally in order to free the emergency exit.

"Any reason you want to go, particularly?" asked Ching, watching the other's inept manipulations. "I'm willing."

"It's all right. I'm going out," said Mishnoff, out of a dry throat, and stepped into the lock that led out onto the desolate surface of a lifeless Earth. A presumably lifeless Earth.

The sight was not unfamiliar to Mishnoff. He had seen its like dozens of times. Bare rock, weathered by wind and rain, crusted and powdered with sand in the gullies; a small and noisy brook beating itself against its stony course. All brown and gray; no sign of green. No sound of life.

Yet the sun was the same and, when night fell, the constellations would be the same.

The situation of the dwelling place was in that region which on Earth proper would be called Labrador. (It was Labrador here, too, really. It had been calculated that in not more than one out of a quadrillion or so Earths were there significant changes in the geological development. The continents were everywhere recognizable down to quite small details.)

Despite the situation and the time of the year, which was October, the temperature was sticky warm due to the hothouse effect of the carbon dioxide in this Earth's dead atmosphere.

From inside his suit, through the transparent visor, Mishnoff watched it all somberly. If the epicenter of the noise were close by, adjusting the second seismograph a mile or so away would be enough for the fix. If it weren't, they would have to bring in an air scooter. Well, assume the lesser complication to begin with.

Methodically, he made his way up a rocky hillside. Once at the top, he could choose his spot.

Once at the top, puffing and feeling the heat most unpleasantly, he found he didn't have to.

His heart was pounding so that he could scarcely hear his own voice as he yelled into his radio mouthpiece, "Hey, Ching, there's construction going on."

"What?" came back the appalled shout in his ears.

There was no mistake. Ground was being leveled. Machinery was at work. Rock was being blasted out.

Mishnoff shouted, "They're blasting. That's the noise."

Ching called back, "But it's impossible. The computer would never pick the same probability pattern twice. It couldn't."

"You don't understand-" began Mishnoff.

But Ching was following his own thought processes. "Get over there, Mishnoff. I'm coming out, too."

"No, damn it. You stay there," cried Mishnoff in alarm. "Keep me in radio contact, and for God's sake be ready to leave for Earth proper on wings if I give the word."

"Why?" demanded Ching. "What's going on?"

"I don't know yet," said Mishnoff. "Give me a chance to find out."

To his own surprise, he noticed his teeth were chattering.

Muttering breathless curses at the computer, at probability patterns and at the insatiable need for living space on the part of a trillion human beings expanding in numbers like a puff of smoke, Mishnoff slithered and slipped down the other side of the slope, setting stones to rolling and rousing peculiar echoes.

A man came out to meet him, dressed in a gas-tight suit, different in many details from Mishnoff's own, but obviously intended for the same purpose-to lead oxygen to the lungs.

Mishnoff gasped breathlessly into his mouthpiece, "Hold it, Ching. There's a man coming. Keep in touch." Mishnoff felt his heart pump more easily and the bellows of his lungs labor less.

The two men were staring at one another. The other man was blond and craggy of face. The look of surprise about him was too extreme to be feigned.

He said in a harsh voice, "Wer sind Sie? Was machen Sie hier?"

Mishnoff was thunderstruck. He'd studied ancient German for two years in the days when he expected to be an archeologist and he followed the comment despite the fact that the pronunciation was not what he had been taught. The stranger was asking his identity and his business there.

Stupidly, Mishnoff stammered, "Sprechen Sie Deutsch?"and then had to mutter reassurance to Ching whose agitated voice in his earpiece was demanding to know what the gibberish was all about.

The German-speaking one made no direct answer. He repeated, "Wer sind Sie?" and added impatiently, "Hier ist fiir ein verriickten Spass keine Zeit."

Mishnoff didn't feel like a joke either, particularly not a foolish one, but he continued, "Sprechen Sie Planetisch?"

He did not know the German for "Planetary Standard Language" so he had to guess. Too late, he thought he should have referred to it simply as English.

The other man stared wide-eyed at him. "Sind Sie wahnsinnig?"

Mishnoff was almost willing to settle for that, but in feeble self-defense, he said, "I'm not crazy, damn it. I mean, "AufderErde woher Sie gekom-"

He gave it up for lack of German, but the new idea that was rattling inside his skull would not quit its nagging. He had to find some way of testing it. He said desperately, "Welches fahr ist es jetzt?"

Presumably, the stranger, who was questioning his sanity already, would be convinced of Mishnoff's insanity now that he was being asked what year it was, but it was one question for which Mishnoff had the necessary German.

The other muttered something that sounded suspiciously like good German swearing and then said, "Es ist dock zwei tausend drei hundert vier-und-sechzig, und warum-"

The stream of German that followed was completely incomprehensible to Mishnoff, but in any case he had had enough for the moment. If he translated the German correctly, the year given him was 2364, which was nearly two thousand years in the past. How could that be?

He muttered, "Zwei tausend drei hundert vier-und sechzig?"

"Ja, fa," said the other, with deep sarcasm. "Zwei tausend drei hundert vier-und-sechzig. Der ganze fahr long ist es so gewesen."

Mishnoff shrugged. The statement that it had been so all year long was a feeble witticism even in German and it gained nothing in translation. He pondered.

But then the other's ironical tone deepening, the German-speaking one went on, "Zwei tausend drei hundert vier-und-sechzig nach Hitler. Hilft das Ihnen vielleicht? Nach Hitler!"

Mishnoff yelled with delight. "That does help me. Es hilft! Horen Sie, bitte-" He went on in broken German interspersed with scraps of Planetary, "For Heaven's sake, urn Gottes willen-"

Making it 2364 after Hitler was different altogether.

He put German together desperately, trying to explain.

The other frowned and grew thoughtful. He lifted his gloved hand to stroke his chin or make some equivalent gesture, hit the transparent visor that covered his face and left his hand there uselessly, while he thought.

He said, suddenly, "Ich heiss George Fallenby."

To Mishnoff it seemed that the name must be of Anglo-Saxon derivation, although the change in vowel form as pronounced by the other made it seem Teutonic.

"Guten Tag," said Mishnoff awkwardly. "Ich heiss Alec Mishnoff," and was suddenly aware of the Slavic derivation of his own name.

"Kommen Sie mit mir, Hen Mishnoff," said Fallenby.

Mishnoff followed with a strained smile, muttering into his transmitter, "It's all right, Ching. It's all right."

Back on Earth proper, Mishnoff faced the Sector's Bureau Head, who had grown old in the Service; whose every gray hair betokened a problem met and solved; and every missing hair a problem averted. He was a cautious man with eyes still bright and teeth that were still his own. His name was Berg.

He shook his head. "And they speak German: but the German you studied was two thousand years old."

"True," said Mishnoff. "But the English Hemingway used is two thousand years old and Planetary is close enough for anyone to be able to read it."

"Hmp. And who's this Hitler?"

"He was a sort of tribal chief in ancient times. He led the German tribe in one of the wars of the twentieth century, just about the time the Atomic Age started and true history began."

"Before the Devastation, you mean?"

"Right. There was a series of wars then. The Anglo-Saxon countries won out, and I suppose that's why the Earth speaks Planetary."

"And if Hitler and his Germans had won out, the world would speak German instead?"

"They have won out on Fallenby's Earth, sir, and they do speak German."

"And make their dates 'after Hitler' instead of a.d.?"

"Right. And I suppose there's an Earth in which the Slavic tribes won out and everyone speaks Russian."

"Somehow," said Berg, "it seems to me we should have foreseen it, and yet, as far as I know, no one has. After all, there are an infinite number of inhabited Earths, and we can't be the only one that has decided to solve the problem of unlimited population growth by expanding into the worlds of probability."

"Exactly," said Mishnoff earnestly, "and it seems to me that if you think of it, there must be countless inhabited Earths so doing and there must be many multiple occupations in the three hundred billion Earths we ourselves occupy. The only reason we caught this one is that, by sheer chance, they decided to build within a mile of the dwelling we had placed there. This is something we must check."

"You imply we ought to search all our Earths."

"I do, sir. We've got to make some settlement with other inhabited Earths. After all, there is room for all of us and to expand without agreement may result in all sorts of trouble and conflict."

"Yes," said Berg thoughtfully. "I agree with you."

Clarence Rimbro stared suspiciously at Berg's old face, creased now into all manner of benevolence.

"You're sure now?"

"Absolutely," said the Bureau Head. "We're sorry that you've had to accept temporary quarters for the last two weeks-"

"More like three."

"-three weeks, but you will be compensated."

"What was the noise?"

"Purely geological, sir. A rock was delicately balanced and, with the wind, it made occasional contact with the rocks of the hillside. We've removed it and surveyed the area to make certain that nothing similar will occur again."

Rimbro clutched his hat and said, "Well, thanks for your trouble."

"No thanks necessary, I assure you, Mr. Rimbro. This is our job."

Rimbro was ushered out, and Berg turned to Mishnoff, who had remained a quiet spectator of this completion of the Rimbro affair.

Berg said, "The Germans were nice about it, anyway. They admitted we had priority and got off. Room for everybody, they said. Of course, as it turned out, they build any number of dwellings on each unoccupied world... And now there's the project of surveying our other worlds and making similar agreements with whomever we find. It's all strictly confidential, too.

It can't be made known to the populace without plenty of preparation... Still, none of this is what I want to speak to you about."

"Oh?" said Mishnoff. Developments had not noticeably cheered him. His own bogey still concerned him.

Berg smiled at the younger man. "You understand, Mishnoff, we in the Bureau, and in the Planetary Government, too, are very appreciative of your quick thinking, of your understanding of the situation. This could have developed into something very tragic, had it not been for you. This appreciation will take some tangible form."

"Thank you, sir."