Raised by remote, astronomer parents on an alien planet, earth-born Lian, 15, plane-crashes 1,000 miles from the observatory to find nice archaeologists from Earth there on a dig. She also falls in love with the amiable, dumb-looking, native ""lumpies,"" squat hexapods whom the people treat as free-roaming pets. Because of Lian's sympathy for the Lumpies (she names her three special friends Cuddles, Poonie, and Naldo), they reveal to her what they've been hiding for generations--they're really not dumb and the mound that attracted the archaeologists is really a wrecked lumpy spaceship, containing a seeming computer which is, for its part, really an electronically-activated distillation of the best lumpy minds of the past. Concern for the lumpies and acceptance by the archaeologists who applaud her find prompt Lian to defy her cold mother and stay on at the dig; the ""computer"" has chosen her as lumpy Guardian though what that means she's not yet sure. Hoover points up a parallel between Lian's situation at the observatory and the lumpies' in a human-tolat culture (the crablike tolats are expert engineers with no imagination)--which neatly ties together the galactic exotica with a standard human-interest drama.