Spring in the first year of high school. Kumiko, a member of the brass band in junior high school, visits the high school brass band club with classmates Hazuki and Sapphire. There, she comes across Reina, her former classmate from junior high. Hazuki and Sapphire decide to join the club, but Kumiko can’t make up her mind. She recollects her experience with Reina at a competition in junior high school.
A new year is starting at Kitauji Kyoto Prefectural High School, and that means clubs are clamoring to recruit new members. The concert band welcomes newcomers and sets their goals for the season. Will they choose to fight for gold at Nationals?
Taki decides to let the band executives choose their competition piece this year. The leadership deliberates on this decision while trying to get the rest of the band ready to perform at the Sunrise Festival.
The concert band begins taking itself very seriously to give itself the best chance possible of winning gold at Nationals. Unfortunately, the intense environment has some of the new recruits discouraged and intimidated.
The day of the Sunrise Festival finally arrives, and it's time for the concert band to have their first performance of the year. Proximity to other schools and bands brings some of Motomu's family issues to light.
Now that she's well into her third-year, Kumiko is now facing pressure from teachers and parents alike to choose what she's doing after high school. Concert band members form groups to attend the Agata Festival, but Kumiko has other plans.
The Prefecturals are coming up and that means the first of many auditions for the members of the concert band. Mayu is still hesitant to audition despite reassurance from the others. Some of Taki's choices for the competition confuse members.
Members of the concert band are given a brief, three-day summer break that quickly fills with plans of all sorts. Some of the third-years attend an event to gather information on different colleges and plan their futures.
The three-day summer camp has begun, and members of the concert band are faced with a rigorous training regimen. Mayu hesitates to audition yet again, afraid that she'll take the soli part from Kumiko. Motomu speaks to Midori in private.
Mayu taking the soli part has made the concert band uneasy. Despite Kumiko's insistence that this is how it should be, several members take issue with Taki's decision.
The Kansai competition is right around the corner, and the band's dissent about Taki-sensei's decisions only continues to grow. Kumiko goes to speak with him, and she has to decide whether to speak her mind.
The concert band receives its Kansai competition results. Reina and Kumiko see Yoroizuka perform with some of their senpais. However, Kumiko and Reina's relationship becomes precarious as she continues to insist she won't go to music school.
Taki decides that the band will choose the euphonium soli player by voting on one final audition. Kumiko then decides that they should choose based on sound alone, and so the two of them audition anonymously.
The final competition for the third-years is at hand. The Kitauji High School Concert Band performs together one last time in a bid for National gold.
