Joseph Breden knew it was a dream when he shot his co-guardian, Carolyn Kohl, through the head. It was a recurrent dream. And it wasn't a safe dream to have, when you were one of the nuclear physicists chosen to be a guardian at Uranium Pile Number One, the key-spot of a civilization that existed a hundred years after Hiroshima.

There was more to the dream—the nightmare sensation of going down into the very heart of the great sunken ziggurat under the Pacific island, and removing the boron dampers so that the atomic pile approached—and reached!—critical mass.

Breden was off beam, and knew it, and knew that the next psych check would betray him to the medical board. Then he'd lose his job, because the guardians at the island had to be perfectly balanced psychologically, His job was vital to him, partly because of Margaret, his wife; partly because of his brother Louis. Louis was one of the mutants born after atomic blasts—there were a number of these. They weren't supermen. They were merely humans extended.