I had been sure the sailors would leave the chamber in which we had found them soon, since there was nothing there for them once they had treated one another’s wounds and caught their breath. In the event, they stayed so long that I was almost convinced we had missed them — that they had gone back to the scene of the fight, or down some branching passage that we had overlooked. No doubt they had disputed long before setting out.

However it had been, they appeared at last. I touched a finger to my lips to warn Zak, though I do not think that was necessary. When all five had passed and seemed likely to be fifty ells or more ahead, we crept out.

I had no way of knowing how long we would have to follow them before Purn would be last among them, or if he would ever be last; in the worst case, I was prepared to pin our hopes on our courage and their fears, and take him from their midst.

Fortune was with us — Purn soon lagged a few steps behind. Since succeeding to the autarchy, I have often led charges in the north. I feigned to lead such a charge now, shouting for pandours who consisted exclusively of Zak to follow. We rushed upon the sailors as though at the head of an army, flourishing our weapons; and they turned and fled as one man.

I had hoped to take Purn from behind, sparing my burned arm as much as I could. Zak saved me the trouble with a long flying leap that sent him crashing into Purn’s knees. I needed only to hold the point of my dagger at his throat. He looked terrified, as well he should: I expected to kill him when I had wrung as much information from him as I could.

For the space of a breath or two we remained listening to the retreating feet of the four who had fled. Zak had snatched Purn’s knife from its sheath, and now waited with a weapon in either hand, glaring at the fallen seaman from beneath beetling brows.

“You’ll die at once if you try to run,” I whispered to Purn. “Answer me and you may live awhile. Your right hand’s bandaged. How was it hurt?”

Although he lay flat on his back, with my dagger against his throat, his eyes defied me. It was a look I knew well, an attitude I had seen broken again and again.

“I haven’t enough time to waste any on you,” I told him, and I prodded him with the point just enough to draw blood. “If you won’t answer, say so plainly; and I’ll kill you and be done with it.”

“Fighting the jibers. You were there. You saw it. I tried to get you, sure, that’s true enough. I thought you were one of them. With that jiber—” His eyes flickered toward Zak. “With him with you, anybody would have. You weren’t hurt, and no harm done.”

“’As the viper told the sow.’ So a man called Jonas used to say. He was a sailor too, Purn, but as quick to lie as you are. That hand was wrapped in bandages already when Zak and I joined the fight. Take the bandages off.”

He did so, reluctantly. The wound had been treated by a skillful leech, no doubt at the infirmary Gunnie had mentioned; the tear in his flesh was sutured now, yet it was clear enough what sort of wound it had been.

And as I bent to look at it, Zak, bending too, drew his lips back from his teeth as I have sometimes seen tame apes do. I knew then that the wild conjecture I had been trying to dismiss was the simple truth: Zak had been the shaggy, bounding apport we had hunted in the hold.

TO HIDE my confusion, I planted my foot on Purn’s chest and barked, “Why did you try to kill me?”

For some men, there comes a moment when they accept the certainty of death, and so are no longer afraid. That moment came for Purn, a change as unmistakable as the opening of an eye. “Because I know you, Autarch.”

“You’re one of my own people, then. You boarded the ship when I did.”

He nodded.

“And Gunnie boarded with you?”

“No, Gunnie’s an old hand. She’s not your enemy, Autarch, if that’s what you’re thinking.”

To my amazement, Zak looked at me and nodded. I said, “I know more of that than you do, Purn.”

As if he had not heard me, he said, “I’d been hoping she’d kiss me. You don’t even know the way they do it here.”

“She kissed me,” I told him, “when we met.”

“I saw it, and I saw you didn’t know what she meant. On this ship, every new hand’s supposed to have an old one for a lover, to teach him ship’s ways. The kiss is the sign.”

“Women have been known to kiss and kill.”

“Not Gunnie,” Purn insisted. “Or anyhow, I don’t think so.

“But you’d have killed me for that? For her love?”

“I signed to kill you, Autarch. Everybody knew where you were going, and that you meant to bring back the New Sun if you could, turn Urth upside down and kill everybody.”

So stunned was I, not just by what he said but by his very evident sincerity, that I took a step backward. He was up in a trice. Zak lunged for him. But though Zak’s long blade gashed his arm, it did not go deep; he was off like a hare.

He would have had Zak after him like a hound if I had not called him back. “I’ll kill him if he tries to kill me again,” I said. “And you may do the same. But I won’t hunt him down for doing what he believes is right. We’re both trying to save Urth, it seems.”

Zak stared at me for a moment, then lifted his shoulders. “Now I want to know about you. You worry me a great deal more than Purn. You can speak.”

He nodded vigorously. “Zak talk!”

“And you understand what I say.”

He nodded again, though more dubiously.

“Then tell me the truth. Wasn’t it you I helped Gunnie and Purn and the others capture?”

Zak stared, then shook his head and looked to one side in a fashion that showed very plainly he did not wish to continue the conversation.

“It was I, actually, who caught you; and I didn’t kill you. I think perhaps you feel grateful for that. When Purn tried to kill me — Zak! Come back!”

He had bolted, as I should have guessed he would, and with my crippled leg I had no hope of overtaking him. By some freak of the ship, he remained visible for a long time, appearing from one direction only to vanish in another, the soft slapping of his bare feet still audible even when Zak himself was out of sight. I was vividly reminded of a dream in which I had seen the orphan boy with the same name as my own, wearing the clothes I had worn as an apprentice, fleeing down corridors of glass; and it seemed to me that just as little Severian the orphan had in some sense been playing my part in that dream, so Zak’s face had taken on something of the long proportions of my own.

Yet this was no dream. I was wide awake and not drugged, merely lost somewhere in the innumerable windings of the ship. What sort of creature was Zak? Not an evil one, I thought; but then how many of the millions of species on Urth can be called evil in any real sense? The alzabo, certainly, and the blood bats and scorpions, perhaps; the snake called “yellow beard” and other poisonous snakes, and a few more. A dozen or two all told out of millions. I remembered Zak as he had been when I had seen him first in the hold: fallow-hued, with a shaggy coat that was not of hair or feathers; four-limbed and tailless, and surely headless as well. When I had seen him next in his cage, he had been covered with hair and had possessed a blunt-featured head; I had supposed my original impression mistaken without ever calling it clearly to mind.

On Urth there are lizards that take on the coloration of the things about them — green if they are among leaves, gray among stones, and so on. They do this not in order to capture their prey, as one might think, but to escape the eyes of birds. Might it not be, I thought, that on some other world there had come into being an animal that assumed the shape of others? Its original shape (if it could be said to possess one) might have been even stranger than the four-legged, nearly spherical thing I had first seen in the hold. Predators do not prey on their own kind, as a rule. What greater assurance of safety could the prey have than the appearance of a predator?