One year after remarrying, Rieko remains the obedient wife to her husband Tatsuo. However, her son Kenta feels uneasy about Tatsuo and begins to see Rieko not as a mother, but as a woman. Driven by uncontrollable desire, Kenta secretly relieves himself beside sleeping Rieko. Though aware of his actions, Rieko chooses to ignore them—until his sincere passion begins to stir her emotions, eventually leading her to give in and become intimate with him. Even as they become aware of the taboo nature of their mother-son relationship, their overwhelming lust cannot be restrained. In the end, this craving proves to be an inevitable instinct inherent to human nature.