After the death of Emperor Taizong of Zhenguan, Li Shimin, he wakes up through time travel in the thirty-sixth year of Qin Shi Huang, becoming the tragically fated Prince Fusu. The deeply suspicious First Emperor will not give him a chance to replay the Xuanwu Gate incident; Li Si is eyeing him hungrily, Huhai and Zhao Gao harbor malicious intentions, and Modu of the grasslands along with the old aristocrats of the six states are restless. Armed with the military and political wisdom of the Heavenly Khagan, he establishes himself on the frontier to train troops and reorganize forces, improve weaponry, maneuver step by step between monarch and ministers, father and son to break the deadlock, and tries his utmost to save the precarious Great Qin empire, staging a historical-style political drama of a game between two kings.