Naoko and her husband are both remarried, and each has a child from a previous marriage. Three years into their remarriage, the couple becomes sexless, and at the same time, her husband's child from a previous marriage begins to take an interest in Naoko's voluptuous body. Frustrated, Naoko finally gives in to her child's "attachment to his mother" and his overflowing sexual desire, and ends up satisfying her sexual needs. From then on, Naoko develops a physical relationship with her child, hiding it from her family...