Kumiko Oumae, a euphonist, swore off music after an incident at the middle school regional concert band competition. She enters high school with hopes for a fresh start. Fate intervenes, and she is surrounded by like-minded people with an interest in the high school brass band. With the support of her bandmates, including new members such as novice tubist Hazuki Katou, veteran contrabassist Sapphire Kawashima, and fellow euphonist and band vice president Asuka Tanaka, Kumiko finds the motivation to make music once more. She is also reunited with old friends, including her childhood friend and hornist-turned-trombonist Shuuichi Tsukamoto and trumpeter and former middle school bandmate, Reina Kousaka. Unfortunately, chaos ensues within the band itself. Their goal of qualifying for the national band competition seems unattainable as they struggle to prepare for the local festival. The situation could change with the help of their new band advisor, Noboru Taki.