Five years ago, when Shiori was a student, she ended up having some sort of relationship with her cousin Masashi due to a minor incident. However, they didn't have sex; she only taught him how to masturbate since he didn't even know about it. Both of them were out of their minds at the time. Since then, things became awkward, and Shiori had been keeping her distance from him. Time passed, and they ended up reuniting... Masashi's monkey-like sex drive drives Shiori crazy!
