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.

Dae-ho, an investigative journalist, seeks to track down the whereabouts of his son who was abducted three years ago. With the help of a detective and a psychiatrist friend, he will retrace his memory of the incident through the use of lucid dreaming techniques.