Lee Hyun (Played by Seo In-guk) has shown a superb IQ since he was a child, but he has also shown a devil-like side, so he was strictly controlled by his father, Lee Joong-min (Played by Jun Kwang-ryul). As an adult, Lee Hyun becomes a professor of criminal psychology. One day, at a crime scene, Lee Hyun meets rookie police, Cha Ji-an (Played by Jang Na-ra). Fate connects Li Hyun and Cha Ji-an closely together, creating a wonderful story....