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