In the prosperous Tang Dynasty, in Luoyang, Ye Yuanan, the daughter of a wealthy official, was always fighting for justice. When a courtesan was murdered, she accidentally met the heroic head of police Zhao Lanzhi. The two worked together to solve the case and got to know each other. Yuanan rescued a mysterious amnesiac man named Mu Le from the market and took him in as a servant. Unexpectedly, the stubborn Mu Le was absolutely loyal to him and gradually developed a love for him. In the cases of Luotian Cave and King Jing's Mansion, the three worked closely together, repeatedly solved strange cases, and thwarted the conspiracy of the national teacher Tianqiao who was hidden behind these cases to seize the treasure Nine Star Rosary. Princess Minghui, a disciple of Tianqiao, fell in love with Lanzhi and threatened Lanzhi to marry Yuanan with his life. Yuanan felt very disappointed and wanted to marry Mu Le out of anger, but was misunderstood by Mu Le. Mu Le was sad and found that he was actually a prince in distress in a foreign land, so he stole the Nine Star Rosary engraved with strange magic and returned to his country for revenge. Yuan'an, Zhao Lanzhi and Minghui followed them, and the four of them worked together to quell the chaos, and they also found true love.