Chiyo Mihama is a child prodigy who has skipped several grades to reach high school. On her first day, she finds that her class is filled with eccentric individuals. Sakaki, who towers over Chiyo, is aloof and intimidating; Tomo Takino is loud and annoying; Ayumu "Osaka" Kasuga is absentminded but skilled at solving riddles; Koyomi "Yomi" Mizuhara is obsessed with diets and loves karaoke despite her terrible singing; and Kagura is a competitive tomboy. As the classmates grow close over time, they share their daily lives together—experiencing school, studying, summer trips, and all sorts of shenanigans!