Yoshio lives alone with Kiyomi, his father's new wife, as his father is frequently away for work. Over time, Yoshio finds himself increasingly drawn to his stepmother. One day, while Kiyomi naps, Yoshio becomes captivated by her vulnerable form. Overcome with desire, he begins caressing her. Deeply moved by his touch, Kiyomi grows increasingly aroused and begins masturbating, lost in pleasure. Catching sight of her intimate act by chance, Yoshio can no longer restrain himself and moves closer, giving in to his forbidden longing.