When Myriam, the mother of two young children, decides--despite the reluctance of her husband--to resume her activity in a law firm, the couple starts looking for a nanny. After a thorough interview process, they hire Louise, who quickly conquers the children's affections, and gradually occupies a central place in the family's home. Everyone will gradually get caught in the trap of mutual dependence, until tragedy strikes. (presentation of the publisher Gallimard)