A European group of mercenaries search for black powder in China; however they are attacked by bandits and a monster and only William and his comrade Tovar survive. While escaping with the hand of the monster, they stumble upon the Great Wall and are captured by General Shao, Commander Lin Mae, Strategist Wang and their army. They are imprisoned in the Great Wall and meet the European Ballard, who was also a mercenary looking for black powder that has been imprisoned in the Great Wall for twenty-five years. Soon they learn that the soldiers are trained to fight monsters called Taotie that attack the humans every sixty years. They are the last outpost protecting the capital. When they suffer attack from the horde of Taoties, William and Tovar also fight helping General Shao. When the Taotie Queen retrieves the horde, they know that they will be massively attacked by the Taoties and their only chance is to kill the Queen. Will the humans survive?