Xiao Xuan, the deposed crown prince of Great Liang, was falsely accused and thrown into prison, about to be subjected to death by a thousand cuts by his younger brother, Emperor Xiao Jingnian. Suddenly, a thunderclap struck, and he foresaw that Great Liang would fall, with a hidden move laid out by the late emperor behind it. The Northern Barbarians launched a massive invasion, the border was in critical emergency, and Xiao Jingnian was forced to ask Xiao Xuan for help. Taking command of the three armies under critical orders, Xiao Xuan rushed to the northern frontier, saw through the enemy's scheme, awakened the dormant Profound Armor Army, and heavily defeated the Northern Barbarians. In this battle, he also uncovered a dark secret: the 'killed in battle' 9th Prince, Xiao Han, turned out to be the commander-in-chief of the Northern Barbarians, stirring up trouble to seize power. When Xiao Xuan returned in triumph to the capital, the late emperor's true imperial edict appeared, but it was ambushed and snatched. The former empress's maid appeared, and a new conspiracy surfaced.