When Tatsuya, the friend of her son, comes to visit, Rinko, the mother, reveals her attraction toward him. Her son notices his mother's feelings and decides to leave the house. Seizing the opportunity, Rinko seduces Tatsuya and invites him to the bath. In the warm water, she tempts him and finally takes his cock into her mouth. This act ultimately leads to creampie sex, all while her son watches from a distance—though Tatsuya remains unaware.