Aiko Asakura, who separated from her husband a year ago, lives a peaceful life as a single mother with her son. The apartment they live in has thin walls, and the sounds of men and women mating next door are often heard. The moans heard every day were enough to stimulate the sexual desire of her son, Yoichi. It was only natural for him to awaken to the opposite sex. However, the woman Yoichi developed feelings of love for... was his mother.