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