In ancient China, a group of European mercenaries encounters a secret army that maintains and defends the Great Wall of China against a horde of monstrous creatures.In ancient China, a group of European mercenaries encounters a secret army that maintains and defends the Great Wall of China against a horde of monstrous creatures.In ancient China, a group of European mercenaries encounters a secret army that maintains and defends the Great Wall of China against a horde of monstrous creatures.