Ker-jon sat on the floor with Cluny-ann, squatting near the dusty stacks which held the un-used physical science books. Not a volume here had been disturbed for perhaps a score of years--perhaps more. Why study the physical sciences when there was no real physical world with which to correlate your findings? Why study them when your universe was bounded with walls of glistening beryl-steel? Cluny-ann sat near Ker-jon, but she kept her back to him, angrily. She'd hardly spoken a word since he returned from the psych-tech's office, and lunch had been a sorry social failure. Now Flam-harol got up, paced back and forth for a time, the dome of his three-ridged head gleaming under the blue lights. He licked his lips, fingered for a moment the central flesh-ridge atop his skull. Then he spoke in his deep, booming voice. "I can't help it if I'm nervous; we mutants have waited long and long for this--" A chorus of "ayes" seconded that, and Flam-harol went on. "We can afford no mistakes. We do or we die--tomorrow. One slip--just one--could be fatal. But in the end, if all goes well, we'll smash the Mutant-making machinery, we'll smash the rule of the Mutant-maker. I don't have to tell you what that means. Whither we came from, that doesn't matter. A world called Urth, but I cannot picture Urth--a huge world a hundred times or more larger than the Ark, a world where you live on the outside, not on the inside. "I cannot picture it, and so I won't try. But this I can picture. A hundred years ago, they started making mutants, to satisfy a warped craving for superiority. Half the people on the Ark now are mutants. Ridge-head, scaled, toe-less--what's the difference? Mutants all, living in the worst quarters, relegated to inferior positions, scorned, ridiculed.... "Tomorrow, we end it; by evening, no more. Equality on the Ark, yes, but that's not of primary importance. We will destroy the machinery which can make mutants. No fresh variants will arise, and that is more important. Now, your plans." Another ridge-head stood up. "At ten hours, twelve minutes, my men take the astro-room." A chunky mutant with scales covering his chest: "We converge, along with Flam-harol's squad, on the armory. Also at ten hours, twelve minutes." Second scaled mutant: "The Mutant-maker's quarters. We take the reins of government at ten hours, thirty five minutes." Lithely, Cluny-ann got to her feet. "The Chamber of Change, at ten hours, forty minutes. I lead my women there, and it is hoped that with so much confusion elsewhere, we'll be able to destroy the machinery. But--" "But what?" Flam-harol said. "We appreciate the aid of you non-mutants. Yet if you have any doubts--" "It's not that," Cluny-ann told him. "I don't think our revolution will be enough; that's all." "What more is there?" "I don't know! If I knew, that would be different. I suspect that the whole thing may start over again before we know it." Flam-harol shook his head. "I don't understand."