Mark, approximately 11/12 years old, goes to live with his aunt Fiona, a crabby loner. Fiona, a naturalist, lives on an island and studies horses. Fiona takes over Mark's education. As their relationship matures, Mark and Fiona face a crisis: one of the island's wild horses has been orphaned. The foal will not survive without their help, yet they are forbidden from interfering in the horses' lives.