When a mysterious virus ravages Joseon, exiled Prince Ganglim (Hyun Bin) returns home to battle infected, flesh-eating peasants. Reluctantly joining Baron Park (Jo Woo-jin) to exterminate these deadly demons, Ganglim must also thwart the ruthless War Minister Kim Ja-joon (Jang Dong-gun). The traitor manipulates this apocalyptic chaos to violently usurp the royal throne.