A rocket ship crew arrive at Saturn's ring, made up of moonlets, and Stiton and Gentry's job was to study these up close by landing on one of then. However, when the ship returns to pick them up eight hours later, the two men are missing, so Commander Maxwell orders one of the moonlets brought aboard so that it could be taken back to Earth, where it is discovered the moonlet is actually a living spore.; People who were witnesses to the explosion of the first hydrogen bomb at Eniwetok in July of 1952 grimly discover a year later that children being born to them are weird mutations that have the intellect of normal adult humans. In fact, when their capabilities begin to exceed those of normal adults, it is decided that something needed to be done to keep the mutants from taking over.