In their last year of middle school, the five band members of CRYCHIC went their separate ways after an unpleasant disbandment. Each wrestling with their own regrets, the girls enrolled in different high schools, hoping never to hear from one another again. Meanwhile, Anon Chihaya transfers to Haneoka Girls' Academy in the middle of the school year. As most students play in a band as a hobby, Anon desires to fit in and spends her first days trying to recruit members for her own band, envisioning herself as the group's vocalist. She befriends Tomori Takamatsu, a shy girl who seems interested but hesitant about joining. As it turns out, Tomori used to be part of CRYCHIC, an experience that has scarred her deeply. Through Tomori, Anon meets Taki Shiina and Soyo Nagasaki, both former members of the same band. Although Taki detests the idea of playing with Anon, Soyo is delighted to help her out. Now with Soyo by her side, Anon's dream of forming a band is within reach—if only she could find a few more members.

The day Sakiko Togawa's privileged life crumbled, she painfully broke her vow to CRYCHIC and left the band behind—an act that tore her heart in two. As days fade into nights, she struggles to make ends meet until a certain cherished memory is tainted, pushing her to the edge. Driven by a fractured sense of purpose and the need to reclaim what she lost, Sakiko forms Ave Mujica, a masked symphonic metal band. Its members are bound not by a shared goal but by the fragile threads of their divergent desires. Together, they weave a haunting masquerade of loss and rebirth, captivating audiences with a gothic musical stage play. But as the girls' ideals collide, the scars of their pasts rear their ugly heads. The brittle facade the girls have built threatens to collapse beneath them, bringing Sakiko to the verge of falling apart.

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. In this rising era of girl bands, Afterglow, Pastel*Palettes, Roselia, and Hello, Happy World! begin to make their appearance as well. Each band, comprised of musicians with their unique personalities, illuminates the stage with its performances. As Poppin'Party returns to the music scene and encounters new friends, the sparkling, heart-pounding music starts to play once again!