Chisato Shoda was troubled... After her painful climacteric symptoms subsided, she felt an unprecedented surge of sexual desire. Upon researching, she discovered that women's sex drive can increase due to an increase in male hormones after menopause. She spent her days trying to manage this strong libido on her own. One day, she found herself alone with her daughter's husband. Coincidentally, her daughter was pregnant, and her husband had become sexless. Learning of this, Chisato made a move on her daughter's husband... "Don't worry about being polite. I know how hard it is to suppress sexual desire." Chisato, who had lived a serious and rational life until this point, finds her inhibitions shattered, succumbing to her instincts and pleasure...