 When her 14 year old son mysteriously vanishes from a Parisian street, Marianne (Binoche) begins a desperate search. She finds little help from the police and so hires a detective (le Bihan) to help on the case. Soon a young girl disappears in a similar manner and her father Samuel (Auteuil) joins the search. Suddenly Marianne and Samuel find themselves drawn into a frightening world they scarcely knew existed...