Hirano will portray Gonda Mari, a former aspiring idol and idol fanatic who has memorized every detail of Japan's idol history since the 1980s. As a teacher in the teen comedy, Hirano's character advises the "I Want to Become an Idol Club" at an all-girls finishing school. The five singers of 9nine will play the members of the "I Want to Become an Idol Club." In the story, the girls' senior student scouted them to debut as idols at the school's culture festival. The singers then form the club and devise outlandish lessons to train themselves as performers.