After his father's remarriage, Taro begins living with his stepmother and stepsister. At first, Rena appears sweet and cheerful, giving off a friendly, innocent vibe during their first meeting. But soon, with the whole family present in the room, she starts touching him under the table and forces him to climax while watching. From that moment on, Taro's fate takes an irreversible turn. The presence of Rena brings a profound change to his life.