Overture of Youth (青春の序曲 Seishun no jokyoku?) is chapter 1 of the Haruchikamanga.
As a result of entrance to high school, Chika aims to be a cute girl that suits the flute from the life he was immersed in volleyball club. While rejoicing to Mr. Kusakabe, a music instructor, I will reunite with my childhood friend Haruta. Chika headed to the music room along with Haruta who had already enrolled in the brass band, but waiting there was a mystery letter addressed to Mr. Kusakabe and a red paint on the blackboard like blood It was an eerie mystery called a musical note.
High school girl Chika Homura is anything but demure and ladylike with her rough, wild ways coupled with her volleyball abilities, until she is inspired on television to take up an instrument. Choosing the flute due to believing it to make her more maiden-like, she joins the Brass Band Club of Shimizu South High School and reunites with her childhood friend Haruta Kamijou who plays the French horn. She is also introduced to the club's teacher-in-charge Mr. Shinjirou Kusakabe, the club president Keisuke Katagiri and identical twins Kae and Sae Asahina, who make up the entire Brass Band Club, much to Chika's shock. The entire club, including Mr. Kusakabe, soon find a musical tune painted in red on the blackboard of the music room, a note for Mr. Kusakabe claiming that he should know that tune, and a wreath of white clovers that, in the language of flowers, mean "revenge". Mr. Kusakabe does not recognise the tune though, and the club split up to their respective homerooms for the time being as classes start. When they return, Haruta deduces that the tune is a cipher, a coded message that only the person concerned can decipher, and identifying it from Bach's unfinished musical piece 'The Art of Fugue' written during his twilight years. Haruta manages to decode the message by lining the up the notes and the numbers on the board, deriving letters from a computer keyboard. Do-2 is "A", and so on. The message says "I love you. Thank you." as a love letter addressed to Mr. Kusakabe from a graduated student. Mystery solved, Haruta and Chika walk home together, with Chika vowing to play the flute properly so she can beat Haruta.