The story goes with Kim Yoo Jung as Oh Ah Ran who gets bullied in her school. She got beaten up so that her body left with bruises here and there. Ah Ran's relationship with her mom can't be said good enough. She is cold and never let her mom talk to her. Her mom found out then that she got bullied. Jo Kang Ja - Ah Ran's mom - asked her who's the culprit. But Ah Ran keeps her mouth closed. Things are getting complicated. As Kang Ja don't want Ah Ran get beat up again, she disguise herself as a student nicknamed Jo Bang Wool.