Beyond the Door (1982)

Nina lives a morbid relationship with her stepfather, who is serving time in prison for the murder of the girl's mother. Nina could exonerate the man - the mother actually committed suicide because she had discovered the relationship between her daughter and her husband - but she prefers to know him in prison in order to dominate and possess him. She succeeds in guaranteeing him a regime of semi-freedom, thanks to the money she obtains by organising parties based on drugs and sexual perversion. A young American man, Matthieu, falls in love with Nina and marries her, but is soon abandoned by her when she goes to live with her stepfather, who has meanwhile come out of prison old, depressed and at the complete mercy of his stepdaughter.