Key Out of Time (Time Traders)

Key Out of Time -- the fourth book in the Time Traders series, following The Time Traders, Galactic Derelict, and The Defiant Agents -- again features Ross Murdock as the hero. Accompanying a group of settlers to the now-empty water-planet Hawaika, he is sent back in time through a Time Gate . . . and must learn to survive ten thousand years in the past!