Alternate history + parallel time and space
After Taizong Li Shimin died of illness, he wandered around for thousands of years and witnessed the national humiliation a thousand years later. When he was angry and refused to fight, he suddenly woke up - he had become Tang Xuanzong in the prosperous Kaiyuan Dynasty!
It happened that Fan Yang of Anlu Mountain raised his troops, and Taizong on the throne had his eyes splitting: "I conquered this world, how can I allow Hu'er to cause chaos?"
The next day at the court meeting, the civil and military officials in the court were shocked to see "Xuanzong" pull out the Emperor's Sword and kick Yang Guozhong over: "Come here! Order all my Xuanjia troops to march in person!"
