Suddenly in Dark Night (1981)
Eugenie, a beautiful but shy young girl, has been living with her stepfather, Albert since her mother died when she was a baby. He is a famous writer specializing in stories of erotica. One day she happens to read one of his "erotic" books and its power so affects her that begins to find herself sexually attracted to him. He notices this, and eventually brings her into his dark world of sexual perversion and murder.