In the 24th year of the Kaiyuan period of the Tang Dynasty, the city of Chang'an was prosperous on the surface, but in reality there was an undercurrent. Pei Mingyuan, a doctor in the household department's branch office, discovered anomalies in the treasury accounts, but his secret investigation led to his death.
After his father was killed, Pei Yan, the son of Pei Mingyuan, was forced to grow up from a carefree boy. He inherited his father's legacy and pursued the truth. At the same time, he discovered that the mystery of his life experience was related to the palace coup twenty years ago.
During his escape, Pei Yan met the mysterious musician Xie Yaoqing. She was actually a descendant of the hidden prince Li Jiancheng. The two formed an alliance for a common goal, but each had their own concerns.
As the investigation deepens, Pei Yan discovers that his father's death is related to the prime minister Li Linfu, which also involves the struggle for the throne between Prince Li Heng and Concubine Wu Hui, as well as a mysterious organization called the "Golden Scale Society".
Pei Yan finally exposed the "Golden Scale Society"'s conspiracy to use the hidden prince's treasure twenty years ago to overthrow the Tang Dynasty, but found that he and Xie Yaoqing were just pawns in a larger chess game.
