In a provincial town, one evening of a funfair, Marie witnesses an erotic scene in a ghost train. She cannot distinguish the face of the woman, on the other hand, the man sees her. Troubled, she flees, but the man, Robert, follows her home. That evening, an ambiguous relationship begins between them. Marie's feelings for him oscillate between desire and fear, especially since the next day, she learns that Robert is accused of the disappearance of a young woman.