Key, is covering up for her deceased twin sister, Kiyun, who died from a car accident a few days after her audition for a band, ANGEL. ANGEL is a popular Hallyu wave K-POP artist and after a Scandal, their population went down into the drains. They decided to add a new member. ANGEL consists of Minho, Jonghyun, Onew and Taemin. Before "Kiyun" joined, Taemin is the only girl in the band. Will ANGEL find out that the real Kiyun is dead? or will Key stay as a cover-up forever?