During experiments to find a cure for Alzheimer's disease, a genetically-enhanced chimpanzee uses its greater intelligence to lead other apes to freedom.

Jung-won and his daughter are on their way to Incheon Airport when a thick fog causes a massive chain-reaction crash on the airport bridge. They get stuck in chaos with a group of people, stranded with nowhere to go. Things take a turn for the worse when mutated military dogs that were secretly being transported escape from their cages and the survivors on the bridge become targets of these deadly animals. As the bridge is shut down and in danger...