As her husband approaches retirement and they tighten their budget by hanging laundry on the balcony, mother Seiko finds herself increasingly lonely. With her husband constantly working late, Seiko begins masturbating in the bathroom to cope with her solitude. One day, her son Wataru overhears her and becomes aroused. Later, while washing clothes in the bathwater, he catches sight of his mother's nipples showing through her wet clothes and her soaked crotch. Unable to control his desire any longer, he finally confesses, "Let me take your husband's place."