Fan Xian is born in the ancient empire of Southern Qing with memories of the 21st century. He lives in a rural town as the illegitimate son of the Minister of Finance, raised by his grandmother. His mother, Ye Qing Mei, was once a celebrated inventor and the founder of the Overwatch Department, the country’s spy network but was killed shortly after her son was born. Fan Xian has since been protected by a blind martial arts expert, Wu Zhu, his mother’s bodyguard. He learned martial arts and the art of poison as a child, also assisted by his knowledge from the 21st century.
After an assassination attempt, he decides to venture into the capital to find out more about his mysterious mother and why anyone would want to kill him, as he perceives himself to be an unimportant person. He also wants to know why he has memories of a sharply different era. In the capital, he accidentally meets Lin Wan Er, the sickly illegitimate daughter of Princess Royal, and falls in love with her. Unbeknownst to him, she is the woman the emperor chose for him to marry so that he would be the new overseer of the Royal Treasury, an institute Fan Xian’s mother established in the palace and currently handled by Princess Royal.
In the capital, however, he gets entangled in the intrigues of the Emperor and the two Princes, as well as the Overwatch Department, leading to him questioning his whole identity and inducing him to find his true life goals, abandoning his original intention to just “enjoy life”.