Chan-woo, a dedicated police officer who has been studying for 5 years, decides to join his friends for dinner to ask for the money needed to apply for his exam. However, he ends up getting drunk and blacking out in a neighbor's room. Upon waking up, he finds a bloody corpse in the room and rushes back to his own room, only to find that his phone is missing. He tries to report the incident but realizes he forgot it in another room.
The next day, as Chan-woo is preparing to report the incident, he realizes he has forgotten his phone in the other room. He quickly grabs a rope and swings over to the next door room outside the window, hoping to retrieve his phone. Once he recovers his phone, he cannot return because of a group of cultists who are evangelizing the neighbors in the hallway.
Desperate to get back to his exam, Chan-woo knows it's the last day he has until he can reapply. With time running out, he must navigate through the cultist's activities and make his way back home safely.