A class of second-year high school students at Yooil High School is forced to play a deadly mafia game during a field trip. As psychological warfare intensifies, Lee Yoon Seo, with her sharp reasoning skills, tries to escape, while class president Kim Jun Hee fights for survival with her sense of justice. Oh Jung Won, the top student but an outcast, must team up with others to survive. (Source: MyDramaList)