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.

After trying to cover up a car accident that left a man dead, a crooked homicide detective is stalked by a mysterious man claiming to have witnessed the event.

HA Yoon-ju becomes the newest member to a unit within the Korean Police Forces Special Crime Department that specializes in surveillance activities on high profile criminals. She teams up with HWANG Sang-Jun, the veteran leader of the unit, and tries to track down James who is the cold-hearted leader of an armed criminal organization.