Narumi Hakobe is a high school student who constantly wears a blank expression on his face. Even in class, he's quiet and unassuming. His joy in life is keeping up with posts from "Efa," a girl who takes lewd photos and posts them on social media. But soon, he finds out that Efa's true identity is none other than...his diligent and popular classmate Mitsuha Koto...?!