During the Yongle period of the Ming Dynasty, serial mysteries occurred frequently in the capital: the minister of the Ministry of Industry was murdered in a secret room, holding half a jade pendant engraved with strange patterns in his hand; hundreds of thousands of stones of grain transported from the granary evaporated overnight, leaving only a few special rice husks at the scene. Lu Zhao, a member of the Royal Guards, led the investigation with keen reasoning, but at a deadlock he met Su Qinghuan, a legendary civil engineer - not only can she decipher complex mechanisms, but she also knows the codes of ancient books very well.
From the initial "professional rivalry" to the "tacit partnership", the two followed the clues of half a jade pendant and actually implicated the secret organization "Shadow Moon Sect" that had been dormant for decades. They not only have to crack the secret room mechanism and the strange robbery in the granary, but they also have to deal with the undercurrent in the court and the pursuit of the killer. They also have to stop the Shadow Moon Cult's conspiracy to use the "Moon Container" to hold sacrifices and open a mysterious treasure house. A journey to chase the murderer across the capital and the border begins. The two detectives join hands, vowing to uncover the ultimate code behind the jade pendant and restore clarity to the Ming Dynasty.
