Lieutenant Commander Frank Jacklin is blown up in a thorium bomb explosion while on the battleship Alaska. He awakens in the body of Winnie Tompkins who had perpetrated the explosion. As Tompkins, he learns of a plot by German agents to poison Franklin D. Roosevelt and he tries to warn the authorities. He continues to become involved in intrigue until another accident restores Tompkins to his body, leaving Jacklin in the body of a dog.
Upon arrival at Proxima Centauri, the Exodus-9 crew detects a mysterious object floating in space. They believe it is an alien threat and are panicked. What follows is a chain of absurd misunderstandings, extreme paranoia, and catastrophic decisions that almost spark an interplanetary conflict... against a piece of human junk. Only a stroke of luck prevents a thermonuclear conflict.
Hale Oakham heads into the mysterious jungle to find the mysterious Sir Basil Addington and his laboratory where he has supposedly discovered amazing secrets about life, including ones which enable him to produce monsters and to change the physical characteristics of humans.