After a modern-day man named Han Ning dies in a car accident, he transmigrates into the body of a good-for-nothing young marquis from the Taiping Marquis Mansion of the Great Xia Dynasty. The moment he opens his eyes, he finds himself in the bed of Princess Royal Xia Qingyue, who forces him into a sham marriage to avoid being sent to the Chu Kingdom for a political marriage. Using modern science, he overwhelms the Imperial College, crushes aristocratic young masters with mathematical algorithms, and becomes famous throughout the capital after winning the title of flower queen with three poems. After becoming embroiled in a tax silver case, he travels as an envoy to the Chu Kingdom, subdues the three Divisions of Heavenly Mandate, and becomes their master. He obtains a secret letter exposing a shocking conspiracy: the Earl of Anyuan hired assassins to murder the Taiping Marquis and support Prince Jing in usurping the throne. At the grand Jingshan sacrificial ceremony, he joins forces with the Princess Royal to expose the Empress Dowager's hidden secrets before fighting a bloody battle against the rebels in Xizhou. Xia Qingyue ascends the throne as the Empress and appoints Han Ning as a first-rank imperial guard bearing a sword. When the rebels in Xizhou rise again, the battle for the new dynasty begins.