Li Hao was originally an immortal who failed to ascend, but traveled through time and became Li Shimin's eldest son. However, due to the conspiracy of Li Jiancheng's forces, he was mistaken for Li Jiancheng's son. His mother, Xiang Fei, was executed. He was also treated as an adopted son and was not welcomed by Li Shimin. Li Hao, who was well aware of the cruelty of the imperial family, asked himself to leave the Li Mansion and become a small farmer. He was grateful for Queen Changsun's support. In order to repay his kindness, Li Hao decided to help Datang rise. However, Li Jiancheng and other villains continue to hinder him. The Tang Dynasty is in trouble internally and externally, and he must resolve the crisis within a limited time. In this process, he faced a dilemma between power and affection. On the one hand, Li Shimin wanted to pass the throne to him after discovering the truth; on the other hand, he yearned for a free life and his affection for Empress Changsun. At the same time, he also encountered many misunderstandings and was misunderstood by all parties. In the end, Li Hao successfully helped the Tang Dynasty become the world's largest country, but he gave up the throne and traveled around the world with the two ladies Fang and Du, leaving a legend.