European mercenaries, including Irishman William Garin and Spaniard Pero Tovar, travel to China during the reign of the Song dynasty’s Renzong Emperor, searching for the secret to gunpowder. A few miles north of the Great Wall, they are attacked by a monster. Only Garin and Tovar survive; they sever the monster’s arm and bring it with them. Upon reaching the Wall, they are taken prisoner by soldiers of the Nameless Order, led by General Shao and Strategist Wang. The Nameless Order exists to combat alien monsters called Tao Tie, which arrived from a meteorite and attack once every sixty years. While examining the severed monster arm, the Order’s commanders are surprised by the monsters’ first assault, which has come one week early.