Nao lives happily with her husband, who runs a company near their home. One afternoon, Jun'ichi Sugaura, a delivery man, comes to deliver a package and immediately falls for Nao when she answers the door. After forcing her into rape and blackmailing her, Nao becomes completely submissive to Sugaura. It's their daily habit for the couple to return home together for lunch, but knowing precisely when her husband comes back, Sugaura begins forcing himself on Nao, making her submit to repeated sexual assaults.