Fumie welcomes her older brother home after returning to her parents' house, while secretly troubled by her shy younger son's breast groping. Unaware of the situation, the eldest son becomes captivated by the sight of his mother bathing and later that night assaults her. The next morning, as Fumie sees her older son off, she indulges in masturbation, calling out his name. Hearing her pleasurable cries, the younger son approaches, signaling a new development.