From mochi*mochi:

Morimura Yuuki, concertmaster at Fujimi Citizens Orchestra, loves music and his small, amateurish, but tight-knit group at Fujimi. His world is shaken up when a brilliant, new conductor, Tounoin Kei, is recruited to breathe life into their music and orchestra. Yuuki feels Tounoin's high demands will do nothing but chase away the members, but when he draws more from them than they ever thought possible, Yuuki reconsiders his own motives for staying at Fujimi. Obviously, the newcomer Tounoin understands Fujimi more than Yuuki ever did and even has the girl that Yuuki's been in love with for the past three years, at his feet. Nursing a wounded pride Yuuki resigns from Fujimi, but Tounoin has other ideas...