Hayashi Shoutaro is an otaku and a student who sucks at studying, the results showing on every test. And if that wasn't bad enough, he also calls out things like, the one who scores the lowest has to clean the classroom by themselves. In his class, there is a girl he likes, Kanda Yayoi, who always gets top scores and is popular among the whole class.
When he arrives home after cleaning the classroom, he's met by his perverted, otaku sister who has him cross-play (cross-dressing cosplay) to go to an anime merchandise display. There he meets Yayoi, who it turns out is also an otaku, and she falls in love with his cosplay persona...?