Being the only daughter of the family might sound depressing. Having three older brothers and all your cousins are guys. Sad right? But not for Han SunHi. Rather then being a spoiled princess, she is more then happy to be the strong tomboy she's become to be. She is in fact one of the guys. When her family decides to move back to Korea, SunHi must adjust to her old surroundings, where being a tomboy is not really accpeted. With glares coming from the left and right, it still doesnt stop her from being who she wants to be. The only person at school that seems to accept it, is her friend Kim Seokjin, who's from a group of boys that goes by the name of BTS. When SunHi meets them, all seem to like her tomboish self, however one doesn't seem he wants to. This is the only beginning of the their bickering.