Captain Joe Storn, shanghaied in Luna, promoted to admiral, and ordered back to space, cannot refuse. Mother Earth is dying. All her creatures need a lifeline. Joe must take a fleet of seven vast freeze-ships halfway across the Galaxy to the Magnus System, where three Earth-like planets promise hope. His ships carry the basic material to recreate every living thing from Earth, including humans, in deep stasis to withstand the 1,000-year voyage.

An unforeseen magnetic anomaly inexorably drags the fleet to the wrong planet, which has some decidedly unfriendly denizens. The worst of these, in Joe's opinion, is the Committee of Captains, a cowardly group formed during his absence. The Committee, after declaring the planet unsafe for human habitation, orders all but a small science team back into freeze because of a virus peculiar to their new home. The infected begin frenzied copulation, often to the point of death. Instead of curing the virus, though, the Committee's scientists abolish sex altogether by concocting a libido suppressant. To ensure everyone imbibes the daily dose, all awake personnel are confined to the ships' immediate area.

Joe and his inner circle are protected from the virus by submicroscopic robots he first developed as protection against radiation in space. The bots repair and enhance right down to the cellular level. The Committee, appalled by the idea of minute "machines" in human bodies, refuses to allow the revival of any of the frozen millions sent to settle this world.

But settling is what Joe was sent to do, and what he intends. First, he and his people have to escape the Committee. When they do, when they learn what the planet, now officially given his name, has in store, only the bravest will succeed. Only the strongest will survive.