The story takes place in the distant Western Han Dynasty. During the reign of Emperor Yuan of Han, the territory of the Han Dynasty had already expanded to the depths of the Western Regions under the continuous conquests of his great-grandfather Emperor Wu of Han. At this time, the Grand Protector of the Western Regions, Huo An (played by Jackie Chan), did not regard himself as the Celestial Empire. He interacted with the countries in the Western Regions in a friendly and equal manner, treated them equally, and resolved the conflicts between the various ethnic groups in a unique way, achieving a peaceful scene that could not be achieved by force alone. Who knew that Huo An was framed and exiled to Yanmen Pass to repair the city. At this time, he encountered the little prince who had fled here from the distant Roman Empire and his guard Lucius (played by John Cusak). After the initial misunderstanding, the two heroes Huo An and Lucius became friends. But with the crisis, the great prince of the Roman Empire, Thebes (played by Adrien Brody), who attempted to seize the throne, led an army of 100,000 to the border, and the two empires of the East and the West were about to collide unprecedentedly...