Go Mi-Nyu, a girl about to become a nun, is asked to cover for her indisposed twin brother, Mi-Nam, who's on the verge of becoming a k-idol. To do so, she disguises herself as a boy and joins A.N.Jell, a really popular boy band. The management company of the idol group A.N.JELL insisted on adding a new singer to the group as the lead vocal's, Tae-Kyung's, voice was hurting. However, the new member Mi-nam, had to go to the States to repair a botched eye job just before signing the contract. His agent came up with the idea of having his twin sister, Mi-nyu, stand in for him and pretend that she was her brother. The two of them grew up in an orphanage and Mi-nyu, who was all set to become a nun, agreed to this charade as she didn't want to spoil her brother's chance of fame which would make it easier to look for their mother.