In a forest in Denmark, a ranger discovers the fresh corpse of an unidentified woman. A large scar on one side of her face should make the identification easy, but nobody has reported her missing. After four days, Louise Rick--the new commander of the Missing Persons Department--is still without answers. But when she releases a photo to the media, an older woman phones to say that she recognizes the woman as Lisemette, a child she once cared for in the state mental institution many years ago. Lisemette, like the other children in the institution, was abandoned by her family and branded a "forgotten girl." But Louise soon discovers something more disturbing: Lisemette had a twin, and both girls were issued death certificates over 30 years ago. As the investigation brings Louise closer to her childhood home, she uncovers more crimes that were committed--and hidden--in the forest, and finds a terrible link to her own past that has been carefully concealed.