A year ago, Asakura Aiko separated from her husband and has since been living a peaceful life with just her son. The apartment they live in has thin walls, and the sounds of neighbors having sex can often be heard. The moaning sounds that are heard every day were more than enough to stimulate her son Yoichi's sexual desires. Awakening to the opposite sex is only natural; however, the woman Yoichi developed romantic feelings for was... his mother.
