Nao and her husband inherit her family bathhouse from her elderly, retired father-in-law. Running it alone keeps them so busy that they lose all time for each other and gradually drift apart. Then Takahashi, a younger regular who always arrives just before closing, begins working there. As Nao spends more time with him than with her husband, loneliness draws them into an affair. Though burdened by guilt, her body remembers the pleasure of sex, and she moans each time his cock repeatedly penetrates her in the main bath.