A classic science fiction adventure from the backlist of Megan Lindholm, who also writes as Robin Hobb. Generations ago humanity abandoned Earth. Now they have returned. Far from home, the Human race tries to atone for killing Terra thousands of years ago. Rescued by the enigmatic Arthroplana in their mysterious Beastships, they have been inserted into the fragile ecologies of the alien twin worlds of Castor and Pollux, where they must make no impact, where…