In Univeil School of Opera, an institution where only male students perform both male and female roles on stage, four classes compete for glory: Quartz, Onyx, Rhodonite, and Amber. This collection of three linked side stories serves as a prequel to the main Jack Jeanne narrative, focusing on the struggles and growth of students from the Amber and Onyx classes.

The first story, Puppet, follows the unnamed top student of the 76th intake, a prodigy who entered Amber class with the highest rank and dreams of becoming Jack Ace, the lead male role. His confidence shatters when Chui Tanakamigi, a younger student with raw, overwhelming talent, enrolls. As Chui rapidly rises through the ranks and claims the spotlight in the summer performance, the protagonist feels his identity as a performer crumbling, reduced to a mere puppet manipulated by someone else's genius.

The second story, Parsley, centers on Shouji Sugan, a first-year student in Onyx class. He entered the school burning with ambition to become Jack Ace, but the first stage performance forces him to confront a painful truth: he is a supporting player, a garnish like parsley rather than the main dish. When his group leader, Gakushin Kaidou, unexpectedly casts him as the lead female role Al Jeanne, Shouji must confront his own insecurities and redefine what it means to shine on stage, ultimately choosing a path he never expected.

The third story, Pecker, ties the two earlier narratives together. Kokuto Neji, a member of Amber class and the stage partner of Chui Tanakamigi, makes a sudden decision to transfer out of Amber and into Quartz. This shocking choice challenges his relationship with Chui and reshapes the future trajectory of both characters, setting the stage for events that lead into the main Jack Jeanne story.