As humans turn into savage monsters and the world plunges into terror, a handful of survivors fight for their lives — and to hold on to their humanity.

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.

A student and a reticent teen first meet at a bakery in the 1990s and try to find each other through the years, as fate keeps pulling them apart.