Yuko, the mother of his childhood friend, was Masaya's first love. Even now, more than half of the time he visits Shiraki's house is to see Yuko. So Masaya noticed the subtle changes in Yuko. She seems lonely lately... That day, Masaya witnessed Yuko masturbating. Seeing her, Masaya strongly wished to comfort her. Of course, Yuko would reject a relationship with her son's friend. So Masaya decided to secretly film her masturbating and use it as blackmail material.