Sound! Euphonium 2 The Hottest Summer of Kitauji High School's Concert Band (響け! ユーフォニアム2 北宇治高校吹奏楽部のいちばん熱い夏 Hibike! Yūfoniamu 2 Kitauji Kōkō Suisōgaku-bu no Ichiban Atsui Natsu ) is the second light novel of the Hibike! Euphonium series, and it was released on March 5, 2015.
The story of second volume focuses on Mizore Yoroizuka, the band's only oboe player, and Nozomi Kasaki, an ex-member who wishes to rejoin the band after she seeing the band's performance in the competition. However, Asuka refuses to let Nozomi back in the band for unknown reasons. Kumiko, who gets wind of this, begins to investigate.
- By order of appearances:
- Nozomi Kasaki, an ex-member, decides to rejoin to the band, triggering the main events of this volume.
- Kitauji's Concert Band starts a three day long band camp.
- Taki-sensei introduces two another instructors to the band, Masahiro Hashimoto and Satomi Niiyama. Everyone starts to think that Satomi is Taki’s girlfriend. Reina is very troubled by this at first, but it turns out that they are just friends, and Niiyama is a married woman.
- There is a swimming pool scene.
- Character development for Asuka, Nozomi, Mizore, Natsuki and Yuuko mostly occurs through dialogue.
- Kumiko builds deeper relationships with Asuka, Nozomi, Mizore, Natsuki and Yuuko.
- The past of Kitauji's Concert Band is revealed in greater detail, including that Nozomi, Mizore, Natsuki and Yuuko graduated from the same middle school. Back then, Nozomi was the band’s president, while Mizore and Yuuko were regular members. Natsuki, however, was not a member in middle school.Their school participated in the middle school level competition, but did not perform well.
- After graduating from middle school, Nozomi, Mizore, Natsuki, Yuuko, and many other band members went to Kitauji high school and joined the band there in hopes of a fresh start. Natsuki also finally decided to join the band in high school. However, these members together got into the conflict with the third year members. Nozomi and most of the first year members who came from the same middle school left the band while Yuuko, Natsuki and Mizore decided to remain for their own reasons.