Junghyun and Juhyun are twins siblings but in different gender. Just because of Junghyun careless side that he injured himself, Juhyun had to disguise herself and be a boy as Junghyun begging her to be. Genie Athletic High School is a private school that only allowed boys to entered it. Juhyun love her twin brother Junghyun and don't want to crash his hope that he really admired want to be in that school since he was little.