Kumiko is now a second year and one of the senior players of the euphonium section. With new underclassmen joining the concert band, Kumiko will have to learn new things in order to deal with awkward and difficult underclassmen. She and third-year trumpeter Tomoe Kabe have been chosen to lead the new underclassmen members. Among the new members to Kumiko's bass section are euphonist Kanade Hisaishi, whose appearances are deceiving; tuba player Mirei Suzuki, who cannot adapt to her new environment; tuba player Satsuki Suzuki, who wants to get along with Mirei; and double bassist Motomu Tsukinaga, who cannot talk about himself. Between the Sunrise Festival, chair placement auditions, and the competition, a number of problems quickly begin to arise.

Officer Mai Kawai has had enough! She’s sick of being a police officer—but just when she’s about to hand in her resignation, the arrival of a brilliant (and beautiful) ace detective named Seiko Fuji changes her mind. Will Fuji reignite Mai’s passion for policing? And will Mai uncover the mystery of why Fuji was transferred to this ordinary police box?

The girls in a high school literature club do a little icebreaker to get to know each other: answering the question, "What's one thing you want to do before you die?" One of the girls blurts out, "Sex." Little do they know, the whirlwind unleashed by that word pushes each of these girls, with different backgrounds and personalities, onto their own clumsy, funny, painful, and emotional paths toward adulthood.