Marie, 35, works at a dingy roadside café in the provinces. She’s reached a touchy moment in her relationship with Henri, a police captain with whom she has a little daughter. They need to take some time out.
One evening, when she’s out with a girlfriend, she catches glimpse of a couple making love in a ghost train. She can’t make out the woman’s face, whereas the man catches sight of Marie’s. Thrown, embarrassed, she flees, but the man won’t let her escape, then won’t let her go, settles in.
An ambiguous relationship develops between them, shifting between fear and desire.