Shortly after her 16th birthday, Ritva is sent away to Seili, an island to the south of Finland. A former leper colony, Seili is now home to 'hopeless cases' - to women the doctors call mad. But Ritva knows she doesn't belong there. As biting winter follows biting winter, she longs to be near to her sister, and wonders why her father ever allowed her to be taken to this desolate place. Hope arrives in the form of Martta, a headstrong girl who becomes Ritva's only friend.