Three years into her marriage, Machiko has begun a secret affair with her husband's older stepson. As she and her stepson grow increasingly intimate, even engaging in steamy encounters in the bathroom during daytime, her younger stepson starts to grow suspicious. Finally, he catches them in the act—walking into the kitchen late at night to find his stepmother kneeling before his brother, his cock deep in her mouth. A shocking revelation exposes the dark secrets hidden within the family.