He was then a sullen, overly matured youth of thirteen, earnest about everything he did--for he knew that the years ahead were grimly earnest. Carefully he kept up with the reports in scientific journals: about the laying of the keel of the first star ship on a minute asteroid with only a number and no name. Harwell was in charge. The propellant would be pure radiant energy--the best of them all; energy so concentrated that it would be truly massive and hurled at the speed of light, which was not remarkable, since it _would_ be light, far more intense per unit area than the noval explosion of a star! This was by no means the only major advance that had been accomplished and was reported. Technological progress was steady in all fields, across the board, making a solid front. Others of its facets also had a special appeal to Ed Dukas. Biological science, in its newest interpretations, he knew to be the most important of these. Now it was no longer just simple rejuvenation--restoring rusty organs. It was a thing that could start from a single cell, in warm, sticky fluids, giving rebirth to something that had already been. And it had a further development--bringing the same results but more swiftly and easily, and with different, far more rugged flesh. It was frightening and fascinating. Knowing was like feeling the shadow of a demon or an angel. * * * * * Ed Dukas and his mother spent four years on their asteroid. Then one day a letter fluttered in her hand. And she seemed not to know whether to look happy or terrified. She did not show her son the letter. "We've had enough of being here," she stated. "We're going home." So they went back across the millions of miles. They cleaned up the house, on which obscene insults had been scribbled in chalk. On two successive days Eddie was jumped by gangs. He fought free and escaped. But on the third evening he was cornered. This time Ash Parker was the ringleader. Ed battled like a bobcat, but eight opponents were too many. He was flat on his back, and they were kicking him. His own blood was in his mouth. What might happen when he blacked out was anybody's guess. Once, before medical knowledge had advanced to where it was, it would have been murder for sure. Somebody intervened--a big guy in a gray business suit who had come striding along the block with an eager attention. He didn't say anything at first. He just collared the toughs, two at a time in swift succession, and thrust them away. Eddie staggered up and faced his benefactor, intent on giving him sincere thanks. "Mister ... I ..." "Hello, Eddie!" the man said, chuckling. "I see you turned out hardy. Seventeen you'd be now." Young Ed Dukas heard the voice and looked at the face. He stiffened. Then he made a statement in a flat tone that sounded very formal and unemotional, which it was not: "Sir, you're my father."