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 teaches him how to survive in the wilderness according to the old ways, and together the boys struggle to build shelter, fashion handmade weapons, and hunt for food and clothing. Still, months of harsh winter weather lie ahead and there is danger everywhere. Will the boys ever see their families again?