A group of girls were recorded as dead in history books from over 10 centuries ago however in reality they were not. In fact, they formed a group, The Six Devils, to eliminate mafias and threats of the government with the orders from the lab where got their powers from at the expense of their memories. The members, JiU, Sua, Siyeon, Handong, Dami and Gahyeon were then sent to a school for both their education and undercover mission. During the time spent in school, they meet a girl who has a small group of friends but was out casted by the rest of the school. Coincidentally, her group friends were the six devil's next targets.