After swearing off music due to an incident at the middle school regional concert band competition, euphonist Kumiko Oumae enters high school hoping for a fresh start. As fate would have it, she ends up being surrounded by people with an interest in the high school brass band. Kumiko finds the motivation she needs to make music once more with the help of her bandmates, some of whom are new like novice tubist Hazuki Katou; veteran contrabassist Sapphire Kawashima; and band vice president and fellow euphonist Asuka Tanaka. Others are old friends, like Kumiko's childhood friend and hornist-turned-trombonist Shuuichi Tsukamoto, and trumpeter and bandmate from middle school, Reina Kousaka. However, in the band itself, chaos reigns supreme. Despite their intention to qualify for the national band competition, as they currently are, just competing in the local festival will be a challenge—unless the new band advisor Noboru Taki does something about it. From the studio that animated Suzumiya Haruhi no Yuuutsu, Kyoto Animation's Hibike! Euphonium is a fresh and musical take on the slice-of-life staple that is the high school student's struggle to deal with their past, find romance, and realize their dreams and aspirations.

The film tells the story of a new transfer student interested in her surroundings, and a song that brings happiness to her and her classmates.

Eight-year-old Tokiyuki Houjou, the next successor of the Kamakura shogunate, is a young boy lacking talent in everything besides hide-and-seek. One day, his carefree life is abruptly turned upside down when Takauji Ashikaga brutally seizes power from the Kamakuras, ending their reign. Rescued by a self-proclaimed prophetic priest, Tokiyuki manages to escape with his life. Now he must evade those trying to kill him while recruiting comrades who can help him restore the Kamakura Shogunate to its former glory. Set during the Nanboku-chou period of Japanese history, is a tale of redemption, documenting the life of the forgotten hero that altered Japan's destiny by running away.

Once a prize-winning violin prodigy, Hajime gave up on music after his father, professional violinist Ryuuji Aono, was involved in a scandal that led the media to harass his family. Now living alone with his mother and entering his final year of middle school, Hajime struggles to find a new career path. However, the sound of his classmate Ritsuko Akine playing the violin inspires Hajime to dream of a musical career once more. With the help of Ritsuko, Hajime prepares to take the entrance exam for the prestigious Umimaku High School. But if he wishes to join Umimaku's orchestra, Hajime must overcome his past trauma and open himself up to new musical horizons.