Kazuki Hihara is an energetic and outgoing third-year music student at Seiso Academy. His extreme vigor is on the verge of being aggressive, but he treats everyone fairly and equally. His bright, endearing smiles are very encouraging though, and despite his almost overwhelming personality, he makes friends easily.
As a competitor in the concours, Kazuki is a very accomplished trumpeter, and he simply wants to enjoy the concours as a music festival with the other participants. He is often seen with Yunoki Azuma, who is not only another contender, but his best friend. However, after meeting Kahoko Hino through the concours, he befriends her straightaway and helps her learn how to enjoy music. There is more to life and music than just joy though; with the help of Kahoko, Kazuki may gather the passion to win the concours rather than just have fun, and along the way, he may discover something he never knew he had in him.