Zia is the 14-year-old niece of Karana, the Nicoleño woman left behind on the Island of the Blue Dolphins in the previous book.

There is evidence on the island that she is still there, including small footprints in the sand, signs of cooking fires, and the remains of huts.

Captain Nidever sails to the Island of the Blue Dolphins to hunt otters, bringing Father Vicente with him to find Karana.

Meanwhile, Stone Hands, planning an escape for himself and the other Native Americans living at the mission, gives Zia the key to the girls' dormitory room.

In the spring, Stone Hands and many of the Native people run away again because of the harsh treatment, and this time Mando leaves with him.

[2] Kirkus Reviews saw that "Zia's narrative continues the laconic precision and sober beauty we remember from Island of Blue Dolphins.