Ritsuko Kawai is a 51-year-old housewife. One night, with her husband away on a work assignment, she decides to indulge in a long-awaited session of phone sex. However, her teenage son Yutaka sneaks into her room and discovers her intimate moment. Shocked and humiliated, Ritsuko tries to pull away, but Yutaka becomes captivated by his mother's sensitive body and gradually begins to seduce her. Though she initially resists, Ritsuko can no longer withstand his gentle yet passionate touch and eventually gives in to his whispered words. This night marks the beginning of a forbidden, incestuous relationship between mother and son, igniting a strange new bond filled with creampie intimacy.