Nobody comes to the remote Scottish island of Bancree, and seventeen-year-old Flora can't wait to move to the mainland when she finishes school. So when a mysterious man and his daughter move into isolated Dog Cottage, Flora is curious. What could have brought these strangers to the island? The man is seductive but radiates menace, while Flo finds a kindred spirit in his daughter, Ailsa.
Meanwhile, several of the men on Bancree have disappeared, unnerving the community. When a body washes ashore, suspicion turns to the newcomers. But Flo suspects something else, even though it seems impossible: She asks local residents for anything they know about "selkies," the mythical women who can turn from seal to human and back again.
Convinced of her new neighbors' innocence, Flo is fiercely determined to protect her friend Ailsa. Can the answer to the disappearances, and to the pull of her own heart, lie out there, beyond the waves?