In 1835, a group of white hunters slay most of an Indian tribe inhabiting an island off California, forcing the survivors to flee the island. Young Karana, realizing that her 6-year-old brother, Ramo, has been left behind, returns to the island.

In 1835, a group of white hunters slay most of an Indian tribe inhabiting an island off California, forcing the survivors to flee the island. Young Karana, realizing that her 6-year-old brother, Ramo, has been left behind, returns to the island. Karana and Ramo are left alone, menaced by a pack of wild dogs. The most ferocious of the dogs kills Ramo, and Karana teaches herself archery and hunts the dog. She puts an arrow in its chest but then takes pity on the animal and nurses it back to health. She and the dog, whom she names Rontu, become fast friends. When another group of hunters come to the island, Karana hides, and although Tutok, a girl in the group, finds her and tries to befriend her, Karana refuses to trust anyone. Years pass, and Rontu dies of old age. Karana finds a puppy and names him Rontu-Aru--son of Rontu. Later, a boat carrying a missionary arrives, and this time Karana decides to trust the strangers. Taking her pets, Rontu-Aru, an otter, and some wild birds she has trained, she leaves the island.