Maigahara Senior High, a prominent music school, has a mystery rumour: if a musical act performs well enough at the annual school festival, additional credit would be inexplicably added to their report. This piques the curiosity of Serina Akesaka, a student who, while energetic, struggles with academics; in reaction to the rumour, she creates the band Irodorimidori and strives to gain the magical extra credit for each of its members. During the second season of the program, Irodorimidori and Nadeshiko Igarashi formally re-open Maigahara's music club. The three new club members create HaNaMiNa, a second band that collaborates with Irodorimidori.