Zelda (1974)

Henry Davis and Zelda are a couple with peculiar sexual tastes. In order to have more freedom, they send their daughter Ingrid to study in a school away from home. They have a relationship with Ursula but, after some time, when they get tired of her, they involve Christian and his wife Clarissa in their erotic games. When Ingrid comes to spend some time home, her presence becomes the catalyst of profound transformations.