O'Dell was inspired by the real-life story of a 12 year old Native American girl, Karana. The author based his book on the life of this remarkable young woman who, during the evacuation of Ghalas - at (an island off the coast of California), jumped ship to stay with her young brother who had been abandoned on the island. He died shortly thereafter, and Karana fended for herself on the island for 18 years. O'Dell tells the miraculous story of how Karana forages on land and in the ocean, clothes herself (in a green cormorant skirt and an otter cape on special occasions), and secures shelter. Perhaps even more startlingly, she finds strength and serenity living alone on the island.