The action takes place in the provincial town of Pornic at the beginning of winter. 18-year-old Laëtitia mysteriously disappears. Early in the morning, her scooter is found abandoned near her house. Local law enforcement officers begin an investigation. They are joined by an experienced investigator who was sent from the center specifically for this case. The police reconstruct the last events in the girl's life and soon find a person who may be involved in the crime. However, Laëtitia's body is never found.