Mikoto (Kasumi Ando) lives with her husband in an old apartment. She has a good relationship with her husband and has no complaints, but their relationship has become monotonous. Then, her husband suggests anal sex... Mikoto refuses, feeling embarrassed and scared of his sudden request. However, for the sake of her beloved husband, Mikoto decides to touch her unknown anal hole. However, a neighbor happens to witness the married woman's act in the afternoon, and Mikoto ends up violating her irreplaceable virgin anal hole...