"I'll stay in here," he told the puppeteer, "if it makes you more comfortable."

"No. We must meet."

Muscles bunched and twitched beneath its creamy skin as the puppeteer nerved itself. Then the door to the transfer booth clicked open. Louis Wu stepped into the room.

The puppeteer backed away a few paces.

Louis dropped into a chair, more for the puppeteer's comfort than for his own. He would look more harmless sitting down. The chair was of standard make, a self-adjusting masseur chair, strictly for humans. Louis noticed a faint scent now, reminiscent both of a spice shelf and of a chemistry set, more pleasant than othcrwise.

The alien rested on its folded hind leg. "Yon wonder wby I brought you here. This will take some explanation. What do you know of my species?"

"It's been a long time since college. Yon had a comniercial empire once, didn't you? What we like to call known space was just a part of it. We kww the Trinocs bought from you, and we didn't meet the Trinocs until twenty years ago."

"Yes, we dealt with the Trinocs. Largely through robots, as I recall."

"You had a business empire thousands of years old at least, and scores of light years across, at least. And then you left, all of you. You left it all behind. Why?"

"Can this have been forgotten? We fled the explosion of the galactic core!"

"I know about that." Dimly, Louis even remembered that the chain reaction of novae in the hub of the galaxy had actually been discovered by aliens. "But why run now? The Core suns went nova ten thousand years ago. The blast won't reach here for another twenty thousand years."

"Humans," said the puppeteer, "should not be allowed to run loose. You will only harm yourselves. Do you not see the danger? Radiation along the wave front will make this entire region of the galaxy uninhabitable!"

"Twenty thousand years is a long time."

"Extermination in twenty thousand years is extermination nonetheless. My species fled in the direction of the Clouds of Masellan. But some of us remained, in case the puppeteer migmtion showd meet danger. Now it has."

"Oh? What kind of danger?"

"I am not yet free to answer that question. But you may look at this." The puppeteer reached for something on a table.

And Louis, who had been wondering where the puppeteer kept its hands, saw that the puppeteer's mouths were its hands.

Good hands, too, he realized, as the puppeteer reached gingerly across to hand Louis a holo print. The puppeteer's loose, robbery lips extended inches beyond its teeth. They were as dry as human fingers and they were rimmed with little fingerlike knobs. Behind the square teeth, Louis caught a glimpse of a flickering, forking tongue.

He took the holo print and looked into it.

At first it made no sense at all, but he kept looking, waiting for it to resolve. There was a small, intensely white disc that might have been a sun, GO or K9 or K8, with a shallow chord sliced off along a straight black edge. But the blazing object could not have been a sun. Partially behind it, against a space-black background, was a strip of sky blue. The blue strip was perfectly straight. sharp-edged, solid, and artificial, and wider than the lighted disc.

"Looks like a star with a hoop around it," said Louis. "What is it?"

"You may keep it to study, if you wish. I can now tell you the reason I brought you here. I propose to form an exploration team of four members, including myself and including you."

"To explore what?"

"I am not yet at liberty to tell you that."

"Oh, come now. I'd have to be off my head to jump as blind as that."

"Happy two hundredth birthday," said the puppeteer.

"Thanks," Louis said, bewildered.

"Why did you leave your own birthday party?"

"That's not your concern."

"But it is. Indulge me, Louis Wu. Why did you leave your own birthday party?"

"I just decided that twenty-four hours weren't enough for a two hundredth birthday. So I went ahead and lengthened it by moving ahead of the midnight line. As an alien you wouldn't understand -"

"You were elated, then, at how well things were going?"

"No, not exactly. No …"

Not elated, Louis remembered. Quite the contrary. Though the party had gone well enough.

He'd started it at one minute past midnight that morning. Why not. His friends were in every time band. There was no reason to waste a single minute of this day. There were sleep sets all over the house for fast, deep cat naps. For those who hated to miss anything there were wakeup drugs, some with interesting side effects, others with none.

There were guests Louts hadn't seen in a hundred years, and others he met daily. Some had been Louis Wu's deadly enemies, long ago. There were women he had forgotten entirely, so that he was repeatedly amazed at how his taste had changed.

Predictably, too many hours of his birthday were spent performing introductions. The lists of names to be memorized beforehand! Too many friends had become strangers.

And a few minutes before midnight, Louis Wu had walked into a transfer booth, dialed, and disappeared.

"I was bored stiff," said Louis Wu. "'Tell us about your last sabbatical, Louis.' 'But how can you stand to be that much alone, Louis? How clever of you to invite the Trinoc ambassador, Louis! Long time no see, Louis.' 'Hey, Louis, why does it take three Jinxians to paint a skyscraper?'"

"Why does what?"

"The Jinxians."

"Oh. It takes one to hold the paint sprayer, and two to shake the skyscraper up and down. I heard that one in kindergarten. All the dead wood of my life, all the old jokes, all in one huge house. I couldn't take it."

"You are a restless man, Louis Wu. Your sabbaticals — it was you who originated the custom, was it not?"

"I don't remember where it started. It caught on pretty well. Most of my friends do it now."

"But not as often as you. Every forty years or thereabouts, you tire of human companionship. Then you leave the worlds of men and strike for the edge of known space. You remain outside known space, all alone in a singleship, until your need for company reasserts itself. You returned from your last sabbatical, your fourth, twenty years ago.

"You are restless, Louis Wu. On each of the worlds of human space, you have lived enough years to be known as a native. Tonight you left your own birthday party. Are you becoming restless again?"

"That would be my problem, wouldn't it?"

"Yes. My problem is one of recruiting only. Yon would be a good choice as a member of my exploration team. You take risks, but you calculate them first. You are not afraid to be alone with yourself. You are cautious enough and clever enough to be still alive after two hundred years. Because you have not neglected your medical needs, your physique is that of a man of twenty. Lastly, and most important, you seem actually to enjoy the company of aliens."

"Sure." Louis knew a few xenophobes, and regarded them as dolts. Life got awfully boring with only humans to talk to.

"But you would not wish to jump blind. Louis Wu, is it not enough that I, a puppeteer, will be with you? What could you possibly fear that I would not fear first? The intelligent caution of my race is proverbial."

"So it is," said Louis. In point of fact, he was hooked. Xenophilia and restlessness and curiosity combined: wherever the puppeteer was going, Louis Wu was going too. But he wanted to hear more.

And his bargaining position was excellent. An alien would not live in such a room by choice. This ordinarylooking hotel room, this reassuringly normal room from the viewpoint of a man of Earth, must have been furnished especially for recruiting.

"You won't tell me what it is you intend to explore," said Louis. "Will you tell me where it is?"

"It is two hundred light years from here in the direction of the Lesser Cloud."