One year ago, Reiko, a beautiful and kind housewife, came to Japan after remarrying. Her new family consists of her husband and her college student boy Tomoma. Reiko is masturbating in her Japanese-style room. Tomoma is walking down the hallway and happens to see the scene. At dinner, Tomoma tells her that he watched her masturbate without meaning to, and he gets angry because he can't do anything because he is worried about Reiko. After having sex with her husband, Reiko is worried about her boy and goes into Tomoma's room. Tomoma suddenly hugs her and asks for her hand. Reiko is confused, but she accepts to have sex with her boy...