High school brass band club members and newly reunited childhood neighbors Haruta and Chika decode a mysterious message hidden in the music of Bach and become rivals in love.

It's now fall and the brass band club has grown. Haruta, Chika, and Miyoko stumble upon Sei Maren, a former saxophonist, at the drama club. The brass band club and the drama club engage in dramatic battle to help Sei come to terms with his past.

Naoko volunteers to help Chika rehearse for the upcoming qualifying round, but wants her help in return. Her aunt has returned to Japan in search of information on her first love and goes to the school's First Love Sommelier for assistance.

According to the will of Mr. Kusakabe's former teacher, his granddaughter, Makoto, is the only one who knows the whereabouts of the key to his beloved piano. Can they figure out the secret of the key's location?

Mr. Kusakabe got an offer to conduct for the Hamamatsu Orchestra. Will he leave the Shimizu South High School Brass Band Club? Why did he skip on the performance as a conductor years before? Haruta and Chika follow him to find out.