But the first visit of Mitchell Prell, when Ed Dukas was five, was, to the boy, like acquaintance with a legend. "Hi, Nipper!" were the first words his uncle had spoken to Eddie. Dr. Mitchell Prell was his mother's brother. He was a much smaller man than Eddie's dad, and dark instead of blond. He was famous. And he brought gifts. "A piece of the Moon, Nipper," he said. "An opal imbedded naturally in gold. For your mom. And this case of instruments dug up in Martian ruins, for your dad. Fifty million years old but better than anything designed by human beings for locating ores far underground. And this for you--also from Mars. I haven't been there for a long time. But I got an old friend to send me the stuff--to the labs on the Moon." Maybe Eddie's gift had once been a toy for the off-spring of extinct Martian monsters. It was triangular like a kite, metallic, with a faint lavender sheen. When you whistled a certain way, a jet of air made it rise high in the sky. But it always came back. Atomic power was in it somewhere. For it never ran out of energy. Uncle Mitch never seemed to say much. He didn't get deep into philosophy. He set up queer apparatus in his room, and a kid could look at it if he didn't touch. And to one of Dad's questions he answered briefly, "Yes, we're making headway in the labs on the Moon. There'll be a motor for star ships. If, in our experiments, hyperspace itself doesn't burst at the seams under that level of power. No, we're not yet trying for speeds of more than a fraction of that of light. A trip to a star will take a long time." It soon came out that Uncle Mitch had another interest. He kept in a glass tube something that squirmed and wriggled, and felt like warm flesh though its natural form, when at rest, was a slender cylinder of pencil size. About that he would only say, "Call it alive if you want to. But not like us. Invented and artificial, and far more rugged than our flesh. For the rest, wait and see if anything comes of it. Maybe it'll become the clay of the superman. Schaeffer, here on Earth, is working on it, too." Uncle Mitch stayed for a week. Then he was gone, rocketing out to the labs, isolated for safety at the center of a _mare_ on the always hidden hemisphere of the Moon. "Mitch knows what he wants and is direct about it," was Jack Dukas's comment. "Simple. No conflicts. The scientist's approach. Wise or stupid? Who knows?" Eddie was six, and then seven. The years moved slowly, but he grew and hardened with them. By the time he was twelve, sports and study and awareness of realities had toughened his body and matured his soul considerably. That was fortunate, for this was his and mankind's fateful year. The day came when the household robots were fixing up the guestroom specially for Uncle Mitch again. Dad was afield, a hundred miles away, to look over a vein of quartz crystal that was to be shipped to the lunar laboratories. At 9:00 P.M. Eddie's father had not yet returned.