Rook wants what any young man strives for, to be recognized as a capable provider by his tribe. One day, while confronting a cougar, he's saved by a terrifying giant boat that travels between the stars, far above, where there's no air. Rook is grateful, but then dismayed to find that everybody he ever knew will be long dead when the boat returns to Earth in a thousand years. The enigmatic space vessel explains that they need Rook's help when they finally do return. And so begins a sequence of visits to his home planet where the "help" that he provides spawns their own puzzling questions. Unbeknownst to Rook and his hosts, however, a rival alien race lurks just beyond the stellar horizon.