Julietta (Dany Robin) is about to enter into a marriage of convenience. When her train stops in Poitiers station, the young girl gets off and the train leaves without her. She audaciously accepts the hospitality of Landrecourt (Jean Marais), a handsome young lawyer. She moves into his house and gets involved in his life...to the great displeasure of Rosie, his fiancee (Jeanne Moreau).