A Girl names 'Choi Ye bin' is one of the biggest fan of 방탄소년단 (Bangtan Soyeondan) or BTS, a famous boygroup in Sopa school in Seoul. BTS are popular in the school because of their face, talent and charm. Yebin's bias in 'Kim Seok Jin' ,the oldest of the group. BTS is a 6-members group but one day a boy names 'Park Jimin' join BTS. He just moves to Seoul and is already popular like the other members. Jimin is Yebin's childhood's friend, who promised Yebin to marry her when they grow up. Now he is back to continue his promise but it is not that easy! Since Jin also likes Yebin, Jimin is loved by anoter a girl. There are many problems between Yebin and Jimin in their school life. Will the promise of Jimin and Yebin come true?