Kazuhiko's father re-married a year ago. His new step-mother, Misako was a beautiful woman, and Kazuhiko can not get her out of his mind. As time has passed Yosuke, his father, has become very cool to her physical & sexual needs. As this is going on, Misako has been getting lewd phone calls and even receives a gift from her caller. As Misako begins to not be able to hold herself back any more, she finds herself trapped within her own desires. After learning that the caller is none other than Kazuhiko her step-son, she begins a decent into lust and long for what her husband will not giver her. But Kazuhiko is not satisfied with just his step-mother. He has also set his eyes on Emiko, Misako's younger sister. What will happen as Misako tries to keep the affair secret from Yosuke and will she loose Kazuhiko to Emiko as they become more deeply involved?