With dreams of becoming a composer and someday writing a song for her favorite idol, Chae Y/N enters the Big Hit Academy, a prestigious performing arts school. If successful there, she'll be able to join the Big Hit Agency after graduation. However, it won't be so easy when Y/N is already surrounded by potential idols and composers.

In the end, right at the graduation, two students are to be teamed up by the choice, one will take the role of the idol and the other should be the composer. They will sing a song that was both composed, written and sung by them. If successful, they will join and take the spot as the new Big Hit Agency debut artists. There is one Absolute rule; ROMANCE is STRICTLY PROHIBITED at their school.