Kang Hyun Se (Kim Jae Won) grew up without knowing his father. Due to the lack of fatherly love, he was recruited by a gang and became a third rate mobster. After his mother's death, he inherits a kindergarten, but he must go through a hundred days of training in order to get it, so he becomes an assistant teacher under a kindergarten teacher, Yoo Mi Rae (Han Ji Min), and they
