Hundreds of years in our future, humanity is expanding out into the galaxy in gigantic colony ships. Slower than light speed, the colony ships are filled with long-lived people who are, nevertheless, in suspended animation for all or much of the voyage. One ship has reached a promising world and begun a colony, but not everyone has yet been awakened. Matthew Fleury is shocked to learn that he has been revived from suspended animation to replace a colleague who has been murdered.

Is the planet still inhabited by the alien race that left ancient ruins of great cities? And who killed the eminent scientist leading the investigation of the ruins? If the aliens survive, then the planet becomes off limits to humans, and the ship must find another planet to colonize. There are some colonists who would kill to leave. And some who would kill aliens, or humans, to stay.