Squirrel and her brother Bone begin their lives in a toolshed behind someone's summer house. Their mother nurtures them and teaches them the many skills they will need to survive as stray dogs. But when their mother is taken from them suddenly and too soon, the puppies are forced to make their own way in the world, facing humans both gentle and brutal, busy highways, other animals, and the changing seasons. When Bone and Squirrel become separated, Squirrel must fend for herself, and in the process makes two friends who in very different ways define her fate.