Barbara is a middle-aged woman in a failing marriage. Her husband is emotionally distant and sexually neglectful. Meanwhile, her college-aged son, Paul (played by Mike Ranger), returns home for a visit. Through a series of emotionally charged, voyeuristic events, Barbara begins to see Paul not as a child, but as a virile man. The film culminates in a famous "seduction" scene, where Barbara deliberately leaves her bedroom door ajar, leading to a sexual encounter that breaks every social convention of the era.
The film was a massive commercial success in the early 1980s and spawned a long-running franchise with over 20 sequels, though the later installments shifted significantly in tone and cast. Taboo 1 1980 Imdb