Flight No. KI501 departs Incheon Airport with its destination set for Hawaii. Veteran police detective In-ho comes across a video message threatening a terrorist attack on this plane and eventually finds out his wife is on board too. He urgently tries to come up with a solution from the ground. One of the passengers includes Jae-hyuk, who is scared of flying and was earlier intimidated by a suspicious-looking man at the airport, finds out that he had boarded the same plane. As he becomes worried, he tries to maintain his emotions towards his daughter. The flight progresses, and a passenger with severe symptoms dies unexpectedly. With the flight crew struggling to resolve the situation, the passengers become frightened as they realize a disaster awaits them. The copilot finds himself making an ‘emergency declaration‘.
