Despite having a son, mother Natsumi invites her lover Koichi over and passionately cuddles with him at home. However, Koichi, troubled by the presence of her son, abandons Natsumi and leaves. Left overwhelmed with pent-up emotions and profound loneliness, Natsumi begins directing her frustration toward her son. Desperate to regain her confidence as a woman, she exposes her body and adopts a provocative attitude. Eventually, her aroused son aggressively mounts her, leading to a shocking series of events.