Young teen Mouchette (Nadine Nortier) faces hardships everywhere in her difficult life. Her father (Paul Hébert) is a cruel drunk who neglects her. Meanwhile, her mother (Maria Cardinal) lies ill, slowly dying. One day, fleeing a rainstorm, Mouchette comes across Arsène (Jean-Claude Guilbert), a poacher with a violent streak. He lets her take shelter in his cabin but then assaults her. Arsène even blackmails Mouchette to involve her in a cover-up for a crime he's committed.