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. A high school girl who's inspired by a gold-medal High Jumper devises a scheme to motivate him by attending his school.