It's the early half of the 19th century in coastal Nova Scotia, and almost-ten-year-old Ellie is adjusting to the recent death of her mother. But just when she finally begins to feel happy again, Ellie and her father move to remote Sable Island, a tiny, windblown crescent of grass and sand in the Atlantic. While her father works, Ellie explores the island, feeling alone and furious with her pa for making them leave their beloved home. Even meeting a spirited island girl named Sarah does little to dispel her anger and grief. Then one afternoon, Ellie encounters a wild stallion grazing on the dunes, and slowly forges a secret connection with the beautiful horse she names Orchid. But Ellie soon learns that Orchid and his family are threatened, and it may be up to her to try and save them.