Kanojo wa Dare to demo Sex suru.

Kazuhiro Sayama has a crush on Sakurai, a quiet and plain-looking girl who sits apart from the rest of the class. While others talk about her behind her back, he believes he knows the goodness in her. However, his world shatters when he witnesses his first love having sex with the despicable gym teacher.

Sakurai confesses that she simply likes to have sex with anyone. Kazuhiro, dreaming of being her white knight boyfriend, instead finds himself forced into the role of her cameraman, documenting her sexual encounters with various men. The only condition: he cannot have sex with her himself.