Plot

Kumiko, a girl with absolutely no ambition, decides to change herself now that she has started her high school life and try to leave her hobby, playing euphonium in orchestra aside but she totally cannot forget it anyway.

Now that Kumiko Oumae has enrolled in Kitauji High School, she hopes to forget about her past. Despite her desire for a fresh start, she gets dragged into the school's band club by her new friends-Sapphire Kawashima and Hazuki Katou-and is once again stuck playing the euphonium. As the band currently stands, they won't be able to participate in the local festival, Sunfest, let alone compete at a national level. The band's new advisor, Noboru Taki, gives them a choice: they can relax and have fun, or practice hard and attempt to get into nationals. Not wanting to repeat her mistakes from middle school, Kumiko is doubtful as to whether they should try for nationals. Amidst the chaos, she learns that her old bandmate, Reina Kousaka (who she had a bitter relationship with) has joined Kitauji's band club. Under the pressure of Noboru's strict training, Kumiko and her bandmates must learn to overcome their struggles and find success together.—MAL Rewrite

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.—Crunchyroll

Spring of the 1st year in high school. Kumiko Oumae who had belonged to the concert band in her junior high school years, visited the high school concert band with her classmates Hazuki Katou and Sapphire Kawashima. And there, she happened to see Reina Kousaka, who was a Kumiko's classmate in her junior high. While Hazuki and Sapphire decided to join the band soon, Kumiko hesitated to do so. Reina reminded her about a certain experience at a tournaments of concert band in junior high school. They will find out precious things through their activities in the concert band. This is a story of the girls' youthful life, filled with their passion and purity.—Kyoto Animation