In the first year of the Tianqi era, mechanical devices flourished, while old and new factions vied for power and plotted chaos. Shen Wen, a scholar from Qinan Prefecture skilled in woodworking and ingenious mechanisms, accidentally becomes entangled in a case involving the theft of a secret imperial treasure one day on the road. This leads him to meet Mu Siqing, the Chief Banner of the Imperial Guards. Shen Wen discovers that the treasure the Imperial Guards are searching for is none other than the Six Harmonies Beast Diagram—the very artifact that once caused the extermination of his entire family. Within the Six Harmonies Beast Diagram lies a hidden secret of the imperial dynasty. In order to find the culprit behind his family’s massacre and unravel the mystery of the Six Harmonies Beast Diagram, Shen Wen decides to secretly scheme his way into the Northern Administrative Office to uncover the truth of the past.