Meguri is living happily with her beloved husband. Her husband always loves and cares for her, so Meguri has a very happy life. But recently, she has always felt like someone is watching her, a picture hanging in the house suddenly disappeared. Especially when the lock was broken, and when she called a locksmith to fix it, they were out of parts, so it took a week to fix. This made Meguri feel extremely worried and uneasy. And her worst fear came true, on ovulation day, she rushed back home because she forgot to lock the door. Suddenly, a masked man attacked Meguri from behind. Unable to resist him, Meguri had to beg in desperation, watching him 'invade' her beautiful and abundant body, ejaculating inside her uterus! The man also took photos of their sexual intercourse and threatened to post them online if Meguri revealed anything. Every day she worries about the man ejaculating into her uterus, fortunately Meguri's menstruation is still regular, so she feels a bit relieved. Since then, a month has passed but the man has not appeared again. Just when Meguri was trying to forget everything, the masked man appeared again on her ovulation day. He continued to have sex with her, ejaculating inside her uterus, and then left. And so, every month, he appears and impregnates her. Meguri always wonders who this mysterious man is, who brings her this mixture of fear and pleasure? And then when he talks to her, she recognizes his voice, he is the locksmith who fixed her house lock before!!!