In 1777, a year into his rule, King Jeong-jo navigates the treacherous life within the palace, supported by his loyal servant Gap-soo, while facing opposition and threats from politically ambitious individuals. At the same time, Eul-soo, a member of a clandestine group of assassins, is tasked with assassinating Jeong-jo. Gap-soo, who was once part of the same secretive assassin organization as Eul-soo, eventually reveals his shadowy past and his reasons for entering the palace to Jeong-jo. To Gap-soo’s astonishment, Jeong-jo inquires about when he abandoned his life as an assassin and instructs him to leave the palace. However, Gap-soo soon learns of another assassin’s presence and rushes back to the court, only to find Eul-soo engaged in a fight with Jeong-jo.