It spoke. Its speech was full of clickings and rustlings and poppings. The flat, hard beak must have been a handicap. But it could be understood.

It said, “Take me to your leader.”

Nick recovered first. He straightened his shoulders, cleared his throat and said, “That will involve a trip of several days. Meanwhile, we welcome you to human space.”

“I’m afraid not,” said the monster. “I hate to ruin your day. My name’s Jack Brennan, and I’m a Belter. Aren’t you Nick Sohl?”

The awful silence erupted in the sound of Luke’s laughter. “You think of it as an alien and you’ll be ready for s-strange — h-hahaha…”

Nick felt panic close around his throat. “You. You’re Brennan?”

“Yah. And you’re Nick Sohl. I saw you once in Confinement. But I don’t recognize your friend.”

“Lucas Garner.” Luke had himself under control. “Your photographs don’t do you justice, Brennan.”

“I did something stupid,” said the Brennan-monster. Its voice was no more human, its appearance no less intimidating. “I went to meet the Outsider. You were trying to do the same, weren’t you?”

“Yes.” There was a sardonic amusement in Luke’s eyes and Luke’s voice. Whether or not he believed the Brennan-monster, he was enjoying the situation. “Was there really an Outsider, Brennan?”

“Unless you want to quibble about definitions.”

Sohl broke in. “For God’s sake, Brennan! What happened to you?”

“That’s a long story. Are we pressed for time? Of course not, you’d have started the motor. All right, I’d like to tell this my own way, so please maintain a respectful silence, remembering that if I hadn’t gotten in the way you’d look just like this, and serve you right, too.” He looked hard at the two men. “I’m wrong. You wouldn’t. You’re both past the age.

“Well, bear with me. There exists a race of bipeds that live near the edge of the globe of close-packed suns at the core of the galaxy…

“The most important thing about them is that they live in three stages of maturity. There is childhood, which is self-explanatory. There is the breeder stage, a biped just short of intelligence, whose purpose is to create more children. And there is the protector.

“At around age forty-two, our time, the breeder stage gets the urge to eat the root of a certain bush. Up to then he stayed away from it, because its smell was repugnant to him. Suddenly it smells delicious. The bush grows all over the planet; there’s no real chance that the root won’t be available to any breeder who lives long enough to want it.

“The root initiates certain changes, both physiological and emotional. Before I go into detail, I’ll let you in on the big secret. The race I speak of calls itself—” The Brennan-monster clicked its horny beak sharply together. Pak. “But we call it Homo habilis.”

“What?” Nick seemed forced into the position of straight man, and he didn’t like it. But Luke sat hugging his useless legs to his chest, grinning with huge enjoyment.

“There was an expedition that landed on Earth some two and a half million years ago. The bush they brought wouldn’t grow right, so there haven’t been any protector stage Pak on Earth. I’ll get to that.

“When a breeder eats the root, these changes take place. His or her gonads and obvious sexual characteristics disappear. His skull softens and his brain begins to grow, until it is comfortably larger and more complex than yours, gentlemen. The skull then hardens and develops a bony crest. The teeth fall out, whatever teeth are left; the gums and lips grow together and form a hard, almost flat beak. My face is too flat; it works better with Homo habilis. All hair disappears. Some joints swell enormously, to supply much greater leverage to the muscle. The moment arm increases, you follow? The skin hardens and wrinkles to form a kind of armor. Fingernails become claws, retractile, so that a protector’s fingertips are actually more sensitive than before, and better toolmakers. A simple two-chamber heart forms where the two veins from the legs, whatever the hell they’re called, join to approach the heart. Notice that my skin is thicker there? Well, there are less dramatic changes, but they all contribute to make the protector a powerful, intelligent fighting machine. Garner, you no longer seem amused.”

“It all sounds awfully familiar.”

“I wondered if you’d spot that. The emotional changes are drastic. A protector who has bred true feels no urge except the urge to protect those of his blood line. He recognizes them by smell. His increased intelligence does him no good here, because his hormones rule his motives. Nick, has it occurred to you that all of these changes are a kind of exaggeration of what happens to men and women as they get older? Garner saw it right away.”

“Yes, but—”

“The extra heart,” Luke broke in. “What about that?”

“Like the expanded brain, it doesn’t form without tree-of-life. After fifty, without modern medical care, a normal human heart becomes inadequate. Eventually it stops.”

“Ah.”

“Do you two find this convincing?”

Luke was reserving judgment. “Why do you ask?”

“I’m really more interested in convincing Nick. My Belt citizenship depends on my convincing you I’m Brennan. Not to mention my bank account and my ship and cargo. Nick, I’ve got an abandoned fuel tank from the Mariner XX attached to my ship, which I last left falling across the solar system at high speed.”

“It’s still doing that,” said Nick. “Likewise the Outsider ship. We ought to be doing something about recovering it.”

“Finagle’s eyes, yes! It’s not that good a design, I could improve it blindfold, but you could buy Ceres with the monopoles!”

“First things first,” Garner said mildly.

“That ship is receding, Garner. Oh, I see what you mean; you’re afraid to put an alien monster near a working spacecraft.” The Brennan-monster glanced back at the flare gun, flickeringly, then apparently abandoned the idea of hijacking the dustboat. “We’ll stay out here until you’re convinced. Is that a deal? Could you get a better deal anywhere?”

“Not from a Belter. Brennan, there is considerable evidence that man is related to the other primates of Earth.”

“I don’t doubt it. I’ve got some theories.”

“Say on.”

“About that lost colony. A big ship arrived here, and four landing craft went down with some thirty protectors and a lot of breeders. A year later the protectors knew they’d picked the wrong planet. The bush they needed grew wrong. They sent a message for help, by laser, and then they died. Starvation is a normal death for a protector, but it’s usually voluntary. These starved against their will.” There was no emotion in the Brennan-monster’s voice or mask-like face.

“They died. The breeders were breeding without check. There was endless room, and the protectors must have wiped out any dangerous life forms. What happened next has to be speculation. The protectors were dead, but the breeders were used to their helping out, and they stayed around the ships.”

“And?”

“And the piles got hot without the protectors to keep them balanced. They had to be fission piles, given the state of the art. Maybe they exploded. Maybe not. The radiation caused mutations resulting in everything from lemurs to apes and chimpanzees to ancient and modern man.

“That’s one theory,” said the Brennan-monster. “Another is that the protectors deliberately started breeding mutations, so that breeders would have a chance to survive in some form until help came. The results would be the same.”

“I don’t believe it,” said Nick.

“You will. You should now. There’s enough evidence, particularly in religions and folk tales. What percentage of humanity genuinely expects to live forever? Why do so many religions include a race of immortal beings who are constantly battling one another? What’s the justification for ancestor worship? You know what happens to a man without modern geriatrics: as he ages his brain cells start to die. Yet people tend to respect him, to listen to him. Where do guardian angels come from?”