Taboo IV: The Younger Generation (1985)

Dr. Jeremy, a popular sex therapist who runs an incest support group, has patients including Joyce and Barbara who have incest relationships with their sons. He is also a very strict father, he sent his two daughters Naomi and Robin to boarding school, the eldest daughter Naomi was caught having sex in the dormitory and kicked out of school. At the same time, Jaremy found out that his wife Alice was having an affair with her brother Billy and angrily kicked her out. Naomi chose to live with her mother. Uncle Billy later revealed that she was her biological father, while Robin chose to live with her father. Naomi seduced her uncle and father, while Robin began to yearn for her father, followed by a breakdown of the family relationship.