Part 2

Already he could feel the invisible rays burning resistlessly through his flesh as if it were water, shifting the cells of his body, working its slow, monstrous alchemy upon him. Peter waited until the changes were unmistakably evident in his skin and hair, and then he smashed all the mirrors in the ship.

The embryos were pulsing with unnatural life, even in the suspended animation of their crystal cells. One by one he allowed them to mature, and after weeks or years destroyed the monstrosities that came from the incubators. Time went by, meaninglessly. He ate when he was hungry, slept when his driving purpose let him, and worked unceasingly, searching for the million-to-one chance.

He stared sometimes through changed eyes at the tiny blue star that was Earth, wondering if the race he had left behind still burrowed in its worm-tunnels, digging deeper and deeper away from the sunlight. But after a time he ceased even to wonder.

And one changeling-child he did not destroy. He fed knowledge to its eager brain, and watched it through the swift years, with a dawning hope....

* * * * *

Peter closed the diary. "The rest you know, Robert," he said.

"Yes," I told him. "I was that child. I am the millionth mutation you were searching for."

His eyes glowed suddenly in their misshapen sockets. "You are. Your brain is as superior to mine as mine is to an anthropoid's. You solve instinctively problems that would take our mechanical computers hours of work. You are a superman."

"I am without your imperfections," I said, flexing my arms.

He rose and strode nervously over to the window. I watched him as he stood there, outlined against the blazing galaxies. He had changed but little in the years that I had known him. His lank gray hair straggled over his sunken eyes; his cheeks were blobbed with excresences of flesh; one corner of his mouth was drawn up in a perpetual grin. He had a tiny sixth finger on his left hand.

He turned again, and I saw the old scar on his cheek where I had once accidentally drawn one of my talons across his face.

"And now," he said softly, "we will go home. I've waited so long--keeping the control chamber and the engine room locked away from you, not telling you, even, about Earth until now--because I had to be sure. But now, the waiting is over.

"They're still there, I'm sure of it--the people, and the Invaders. You can kill the Invaders, Robert."

He looked at me, a little oddly, almost as if he had some instinctive knowledge of what was to come. But he went on swiftly, "On Earth we had a saying: 'Fight fire with fire.' That is the way it will be with you. You are completely, coldly logical, just as _they_ are. You can understand them, and so you can conquer them."

I said, "That is the reason why we will not go back to Earth."

He stared at me, his jaw slack, his hands trembling. "What--what did you say?"

I repeated it patiently.

"But why?" he cried, sinking down into the chair before me. In an instant all the joy had gone out of him. I could not understand his suffering, but I could recognize it.

"You yourself have said it," I told him. "I am a being of logic, just as the beings who have invaded your planet are. I do not comprehend the things which you call hate, fear, joy and love, as they do not. If I went to Earth, I would use your people to further my knowledge, just as the invaders do. I would have no reason to kill the invaders. They are more nearly kin to me than your people."

* * * * *

Peter's eyes were dull, his limbs slumped. For a moment I thought that the shock had deranged his mind.

His voice trembled when he said, "But if I ask you to kill them, and not my people?"

"To do so would be illogical."

He waved his hands helplessly. "Gratitude?" he muttered.

"No, you don't understand that, either."

Then he cried suddenly, "But I am your friend, Robert!"

"I do not understand 'friend,'" I said.

I did understand "gratitude," a little. It was a reciprocal arrangement: I did what Peter wished, so long as I did not actively want to do otherwise, because he had done things for me. Very well, then we must not go back. It was very simple, but I knew that he could not comprehend it.

I tried to explain it to him, however. But he only stared at me, with an expression on his face that I had never seen there before, and that, somehow, I did not like to see. It was disquieting, and so I hastened to the end that I knew was inevitable.

"Will you promise," I asked, "to abide by my decision?"

He kept on looking at me, his lips trembling in their fixed grin. "No!" he said. "Never! You'll change your mind some day--you must! We'll go back, then--I'll make you go back! Lorelei--" He collapsed, sobbing, his head sunk in his arms.

I knew that what he said was partly true. Some day, when I slept, as I would have to within months, he would go down to the control room, set the keys for the return, and lock the combinations of the doors behind him again. Sooner or later, in spite of me, _The Avenger_ would go home. There was only one thing to do.

He was still slumped in his chair, his body shaken by his sobs. I rose silently, and stood for a moment looking down at him. It was best that it happen now; it was what he would have called "mercy."

_I extended my arms, looking at the corded, black-furred length of them. I looked down at him once more, saying a silent farewell; and then I clasped his gray head, very quickly, between my hands._