A passenger flight departs from Incheon to Honolulu. While a Seoul police officer, following his professional intuition, is investigating the identity of an unknown person who posted a video online threatening to carry out a terrorist attack on the plane, the criminal gets on board and sprays an unknown substance there. Passengers and staff begin to show signs of infection with an unknown disease, and it becomes clear that the vessel has been subjected to a bioterrorist attack. The operational headquarters is trying to arrange for the plane to land, but it turns out to be not so easy.