A public service worker at Oksu Station witnesses a shocking incident and recruits his friend to help uncover the truth behind the station's mysterious happenings.

Won-cheol of the National Intelligence Service of the Republic of Korea is offered a mission. Eliminating VIPs who participated in the operation to develop weapons of mass destruction in North Korea. Won-cheol is forced to accept the mission while thinking of her daughter 'Ah-reum' who is in danger - The secret operation of South and North Korean special agents begin.

The story of Joseon's tyrant king Yeonsan who exploits the populace for his own carnal pleasures, his seemingly loyal retainer who controls him and all court dealings, and a woman who seeks vengeance.

Kyung-chul is a dangerous psychopath who kills for pleasure. He has committed infernal serial murders in diabolic ways that one cannot even imagine and his victims range from young women to even children. The police have chased him for a long time, but were unable to catch him. One day, Joo-yeon, daughter of a retired police chief becomes his prey and is found dead in a horrific state. Her fiance Soo-hyun, a top secret agent, decides to track down the murderer himself. He promises himself that he will do everything in his power to take bloody vengeance against the killer, even if it means that he must become a monster himself to get this monstrous and inhumane killer.