Two teenage boys are recording their exploration of the abandoned Gonjiam Psychiatric Hospital, where rumor states that the director of the hospital killed all of the patients and went missing. The two head to Room 402, the intensive care unit, which no one has opened before. They try to open the door but suddenly hear a ping pong ball. Their broadcast abruptly ends. After seeing news of the teenagers' disappearance, Ha-Joon, the owner of YouTube channel "Horror Times", decides to explore the building as well.