This story about a gang of friend who is being best friend since primary school , now they are studying at SEONYOO High School.This gang is always happy together. But one day , Key know that he was got  heart disease. When his Jaejin,Sooyoung and Jessica ask him about his about his health he do not tell them because he do want his friend worry about his self.Sooyoung was falling in love with Key after Key knows that he was got heart disease, on the same day , Jaejin also falling in love with Sooyoung that love his bestfriend Key, Jessica was love Jaejin since primary school was ready to tell Jaejin about her love.What happen to this gang ?? Jessica was ready to tell her love to Jaejin but Jaejin is love Jessica's bestfriend, Sooyoung ! Conflick !!