Time-travel for archaeologists was a well-guarded secret; but when the remains of an interstellar spaceship are uncovered along with the usual fossils, the time agents must call on a modern Apache Indian, Travis Fox, to guide them in the ways of his ancestors in their trip to the past. But the explorers become trapped in space as well as time, on a mad journey in an automatic starship; not even Travis Fox can tell whether any of them will ever see Earth again.