One by one, the crafty members of a destitute family insinuate themselves into the household staff of a wealthy couple living in oblivious privilege.

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.

Two apathetic police academy recruits who become best buddies through the tough training together witness a woman being abducted right before their very eyes. As they were taught in the academy, they quickly report the incident to the police, but the police are in no hurry to jump on the case. So the duo decide to take the matter into their own hands and rescue the woman.