The family of four lives a happy life, but Sakurako, the wife, is frustrated by her husband's lackluster sex life and relieves it by masturbating every night. Sakurako is troubled when her husband's brother, who lives with them, pressures her into a relationship, and although she consults with her husband's stepchild, they end up having a relationship and have intense raw creampie sex. Sakurako is pressured by her brother-in-law again, and cannot forget the taste of immoral pleasure, so she climaxes with a raw creampie during obscene family sex. Sakurako's strange but happy family life begins as she has physical relationships with three men...