“Da-Kyung”, an elite gang member, loses her boss, who was like a mother to her. After realizing that all of this was “Chairman Lee's” doing, there was nothing she wouldn't do to take revenge. However, it is not easy to approach the person behind the “private group”. Just when she was about to give up, she got information about Chairman Lee's son. For her final mission, Da-kyung goes undercover at a chaebol high school...