Daoun is a young, ambitious woman in her first year of teaching high school. Handsome, dark and mysterious, "prince charming" Ryumin flunked his senior year and is a student in her class with a devastating crush on his teacher. And Hyunwoo, a former classmate and fellow teacher of Daoun's, has been in love with her for years but doesn't have the courage to tell her. As Ryumin's advancements toward Daoun increase and Hyunwoo starts to notice, will Daoun follow her head or her heart?