Chang Sun Han (Chang Sun of Xianbei), a top modern historian, and Yu Wenlie (Yu Wen of Xianbei), a military weapons expert, both passed through the prosperous Tang Dynasty in an archaeological accident. Changsun Han became the sick and dormant Li Longji of Emperor Xuanzong of the Tang Dynasty. He awakened the "Emperor's Grand Plan System" and used power and intrigue to save the prosperous Yuan Dynasty from falling. Yu Wenlie was reborn as the legitimate son of the Yuwen family, a border warrior. He awakened the "Tiangong Destroying Army System" and relied on military innovation to protect thousands of miles of rivers and mountains from the smoke of war. One is strategizing in the palace, the other is showing off on the battlefield, the two systems resonate, and the two protagonists join forces to compose a long song of Cangque that subverts history in the turbulent Tang Dynasty and the battlefield outside the Great Wall.
