Island of the Blue Dolphins is based on the true story of a Native American woman who spent 18 years alone on San Nicolas Island, off the coast of California (from about 1835 to 1853). In the novel, twelve-year-old Karana is a member of a tribe that fishes and gathers roots. Her life is shockingly changed when Aleuts and Russian fur hunters come to her island and incite a battle. Her father and many other men are killed.

The tribe’s new chief goes east and sends back a ship to move the tribe to the mainland. Just as the ship is about to leave, Karana’s brother, Ramo, goes off to get his fishing spear and is left behind. Because a storm is expected, the ship cannot wait for him. Karana jumps off the ship, swims back to the island, and stays with Ramo.

Karana and Ramo live in hope that the ship will return, but it does not. Ramo loses his life when he is attacked by a pack of feral dogs. Now entirely alone, Karana develops a close bond with the animals and the natural world of the island. Many years later, another ship arrives and Karana is rescued. She and her dog, Rontu-Aru, are taken to the mission in Santa Barbara, California, to begin a new life.

In the real events on which the novel is based, the Native American “Lone Woman” who was rescued from San Nicolas Island was the last surviving speaker of her language. She was assigned the name Juana Maria. Since 2009, her island has become a place of significant archaeological interest.