Choi Sulli was in a group with four other girls, F(x). She had two closest bestfriends that was in the same company as her, Park Chanyeol and Oh Sehun who was in a group called EXO. Sulli would always hang out with her bestfriends when they don't have any schedules or atleast just a chit-chat between schedules.  

Chanyeol and Sehun were inlove with Sulli and would do anything to try to get her and their friendship may fall apart between them.  But Sulli did not know anything about her bestfriend's crushes but her members realize that the two do like Sulli but kept it a secret.

They had to know who will belong to who.

They had to know who hearts will be belong to who.

♥