Movie
Description
Kumiko Ōmae joins Kitauji High School's concert band as a euphonium player, initially reluctant after encountering her middle school acquaintance Reina Kousaka. Their relationship had been strained following their previous band's failure to advance to nationals despite a prefectural gold award, an outcome Kumiko had pessimistically called impossible.

Indecisive and introspective, Kumiko often questions her own motivations and struggles with social interactions, finding it difficult to express true feelings or confront others directly. Yet she demonstrates kindness and empathy towards friends and bandmates. Her commitment to the band strengthens through high school, fueled by a growing passion for music and a desire for excellence, significantly influenced by her deepening friendship with Reina.

In her second year, Kumiko mentors new first-year students Kanade Hisaishi, Mirei Suzuki, Satsuki Suzuki, and Motomu Tsukinaga. She navigates band conflicts, resolving a misunderstanding that led to Mirei Suzuki temporarily quitting after the Sunrise Festival. Kumiko also experiences a brief romantic relationship with childhood friend Shūichi Tsukamoto; they mutually agree to break up to focus on band commitments before the Kansai competition, where the band receives a "dud gold" and fails to advance to nationals.

As the band president in her third year, Kumiko feels inadequate compared to previous leaders like Asuka Tanaka and Yūko Yoshikawa, believing they handled challenges more effectively. Her leadership involves actively mediating conflicts—such as issues involving new transfer student Mayu Kuroe and tensions between siblings Suzume and Tsubame Kamaya—often prioritizing reconciliation and understanding over confrontation. This approach, while sometimes exhausting her, earns band members' respect and is noted by advisor Noboru Taki as a strength.

Kumiko's parents are Kentarou and Akiko Oumae, and she has an older sister, Mamiko. Mamiko originally inspired Kumiko to play euphonium but quit band for academics. Kumiko experiences periods of tension with Mamiko regarding unspoken regrets, though they eventually reconcile. Her development culminates in confronting future uncertainties, including career choices, while maintaining the band's goal of winning gold at nationals—a promise made with Reina during their first year.