Mika Katagiri, a brown-haired woman, comes from a family running an udon shop in Shizuoka. She serves as the percussionist and leader of a band practicing at a local studio, embodying a determined and strong-willed personality. This determination manifests as blunt, sometimes harsh reactions towards others, particularly when frustration arises from mistakes or setbacks; she openly criticizes or insults people in these moments. Yet beneath this abrasive exterior lies Mika's own dissatisfaction with her interpersonal approach and a genuine desire to connect better with others.

Her driving goal is securing a performance slot for her band at an upcoming local festival. This ambition faces critical challenges: the band's keyboardist abruptly quits shortly before the event, and festival organizers cancel their slot without explanation. Confronted by the dual crisis of a missing member and a revoked opportunity, Mika refuses to accept defeat. She spearheads the effort to overcome both obstacles, actively campaigning the festival planners to reverse their decision while simultaneously grappling with the incomplete band lineup. Her persistent actions throughout this crisis underscore her dedication to achieving the band's performance goal.