Masaki struggles with a taboo obsession for his beautiful mother, leading to a complex and sexualized dynamic of punishment and release. When his friend Miki discovers the truth about Masaki's desires through a shocking encounter at his home, she is encouraged by his mother to step in and help satisfy his needs, sparking a dangerous new arrangement.
Miki continues to assert her dominance over Masaki through teasing and physical control, establishing herself as his superior. The dynamic shifts when Masaki's mother enters, and Miki reveals the pair are not blood-related, using this secret to manipulate the mother into a sexual competition. Ultimately, Miki subordinates both of them, turning the family into her devoted slaves.