Now that Kumiko Oumae has enrolled in Kitauji High School, she aims to leave behind her past experiences. Despite her desire for a fresh start, she finds herself drawn into the school's band club by new friends Sapphire Kawashima and Hazuki Katou. As they currently stand, the band won't be able to participate in Sunfest or compete at a national level due to their limited skills on the euphonium. Their new advisor, Noboru Taki, offers them two options: relax and have fun, or practice hard and try for nationals. Kumiko hesitates as she fears repeating past mistakes from middle school. Amidst the chaos of the band club, she learns that her former bandmate Reina Kousaka has joined Kitauji's band club. Under the strict training regimen imposed by Noboru Taki, Kumiko and her bandmates must find ways to overcome their struggles and achieve success together.
Kumiko is drawn to Kitauji High School's concert band, still haunted by Reina...