While investigating a terroristic threat that goes viral online, Korean authorities discover that a suspect has recently boarded an international flight bound for the United States. When a healthy passenger on the same flight suddenly dies a gruesome death of unknown cause, panic erupts both in-flight and on the ground. With steadily decreasing fuel and international refusals to offer aid, the captain and crew will be forced to take unprecedented emergency measures in an attempt to save the lives of their passengers.

Soo-hyun, who has recently moved into a new house, buys a used washing machine through a second-hand app but finds out it doesn’t work. Annoyed by the seller’s irresponsibility, she leaves a comment calling the seller a con man, and reports it to the police. Little does she know that the seller is a psychopathic serial killer who uses an online second-hand market to lure his victims. Her comment renders his hunt for a new victim all but impossible so she becomes his next target. She starts receiving obscene phone calls, countless unwanted food deliveries, and strange men knocking on her door looking for a good time. A trip to the sender’s address proves deadly serious when the police and Soo-hyun find a man’s dead body.

Reporter Na-yeong and her partner investigate a series of mysterious deaths and a perplexing case where her source was allegedly already dead at the time of their interview. Together they end up confronting a terrifying truth.

A corrupt customs official joins forces with a vicious gangster to form the most powerful crime partnership in Busan.

Ha Yoon-ju becomes the newest member of 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.