Case awakens on a star ship with no memory of his origin. He is told that he is the sole survivor of a ship that his alien benefactors assume came from an undiscovered system. He struggles to make sense of the flashes of unconnected memories that plague him as he searches for his home world. In the process of searching for his true identity, he learns about the many species of humans who travel among the starts and discovers humanity's role among a galaxy- spanning alien civilization.
While evading inimical forces are vying to learn of his origin, he begins to have doubts about his allegedly altruistic caretaker's motives. As his memories become coherent, he confronts possible theories of his origin: what if his ship's drive was an unknown method of FTL; what if he'd come from a colony lost in the early days of mankind's expansion; what his ship had traveled in time; or perhaps his memories were all false and created for some unknown purpose? Each of these ideas is considered, discussed, and discarded as he finally comes to terms with his new identity.