Sulli is 17 years old but doesn't want to live with her parents anymore and is constantly fighting with them about moving out. As she's out with friends one day, they discover an all boys highschool near her house which is the only one she can possibly attend without her parents finding out. Not wanting to bother her friends families, Sulli gets lessons from Amber on how to act like a boy. After changing her disguise, Sulli is transformed into a boy! They get her into the highschool and there she bumps into Taemin, a mean and bossy guy in the school and they later find out that they live in the same dorm. As time passes, Taemin and "Sulli" get close with one another but Taemin starts to realize that there is more to "Sulli" than he thought....