Mikami harbored secret masochistic desires but could never reveal them to anyone, eventually marrying and keeping her feelings hidden. By chance, her husband's older brother discovered her secret. The brother, possessing dominant sadistic tendencies, became intensely interested in Mikami. As a result, the two entered into a BDSM relationship. Through her brother-in-law's strict training, Mikami gradually released her suppressed desires and discovered a new side of herself. This illicit bond became a source of emotional liberation and intense pleasure for her, marking the beginning of a new life.