Kasumi Toyama and the members of Poppin'Party—their high school band—are now second-year students, but with the new school year comes their latest set of challenges: student council duties, cram school, and part-time jobs, among other things. Furthermore, they are now separated into different classes, and as a result, their free time together is shortened. Looking back, their joyful times together seem like nothing more than an unachievable fantasy when their members are too occupied to even gather in Arisa Ichigaya's basement for practice sessions. As the band ponders over the situation, an unfamiliar girl suddenly emerges, unknowingly pulling them into the spotlight once more.