When two mercenaries (Matt Damon, Pedro Pascal) are imprisoned at the Great Wall of China during their search for gunpowder, they discover the true reason it was built. As waves of supernatural creatures that, according to legend, "awaken" every 60 years besiege the Wall, their quest becomes a journey of heroism. The two mercenaries join forces with a massive army manned by the best warriors of China to confront this seemingly unstoppable force.