While her husband is away on a work assignment, married woman Sachiko comes under the care of her father-in-law. Sachiko, who has been having an affair with her husband's older brother, is exposed one day when her father-in-law discovers the truth. Though he has long harbored intense desire for her body, this incident becomes the catalyst for a dramatic shift in his behavior toward her. As their interactions grow increasingly charged, the reasons behind her actions slowly come to light. A delicate, emotionally complex drama unfolds, driven by tangled feelings and raw desire.