During her husband's work-related absence, Rin falls into a relationship with her own son. Though she intended it to be a one-time affair, her feelings grow deeper, and the relationship continues even after her husband returns home. Drawn to her son's youthful, vigorous body, Rin becomes obsessed with their sex life. Her sensitive, voluptuous breasts become aroused instantly, drenched with desire. Even in conversations with her husband, she remains lost in fantasy, unable to stop thinking about the intimate moments she shares with her son.