Thomas and his friend Pitamakan, a Blackfoot boy, live at Fort Benton on the western frontier. One day, having ventured into the mountains to trap beaver, Tom and Pitamakan are attacked by a band of Kootenay Indians, who spare their lives, but make off with everything they have. The boys are stranded without horses, with no food or weapons, without shelter or any means of building a fire. Tom is sure they're going to die. But Pitamakan...