When a crime organization from North Korea crosses borders and enters South Korean soil, a South Korean detective must cooperate with a North Korean detective to investigate their whereabouts.
Lee Chung is a Prince of Joseon, but he has been taken hostage to the Qing Dynasty. He enjoys boozing, womanizing and gambling. He is also an excellent swordsman. His older brother Lee Young will succeed to the throne and brings Lee Chung to Joseon. He returns after more than 10 years. Soon, Lee Chung faces monsters that run rampant in the night.
An ace police crisis negotiator, Chae-yoon, is called to the scene where her supervisor is taken hostage. Through the control room monitor, she is faced with the cold-blooded hostage taker, Tae-gu, whose demeanors are difficult to interpret. Against the 21-hour deadline Tae-gu has set, Chae-yoon tirelessly tries to crack the unusually calm perp over multiple video-calls. Eventually, the shocking truth begins to unveil.
A con man who had been reported dead after committing a historical fraud case is rumored to be alive. Prosecutor Park who was in collusion with the con man needs to eliminate him to avoid a corruption scandal. During his pursuit of the con man, he meets Ji-sung who is also after the same man for a personal revenge. Realizing their mutual goals, they decide to team up, but with hidden motives.