Ami, a married woman, begins living with her husband's father, Taizo. Unable to resist his desire for her young body, Taizo rapes Ami. From then on, he constantly takes advantage of any opportunity to molest her, forces her into sex with her husband, spies on her intimate moments, and subjects her to depraved humiliation even beside her sick son as he sleeps. Trapped in this relentless torment inflicted by her stepfather, Ami gradually suffers intense psychological anguish.