Amane Kojou, a sporty high school student, has a steady boyfriend her own age, Kouta, but for some inexplicable reason, he doesn’t want to sleep with her. Instead, she has to masturbate alone at home every night. However, this has not gone unnoticed by a middle-aged man who, having been an athlete himself, sometimes accompanies her on her way to school. He secretly holds his mobile phone camera in her room from a blind spot so he can watch what is happening. After he has once again gone running with her, despite his obesity – something her lazy boyfriend would never do – he finally shows her the video he has made. If she wants him to delete the recordings, she must first sleep with him …