Li Mengjue and Xie Jingshu become a contractual "hundred-day couple" due to the Huachao Tower Incident. In the eyes of outsiders, the two are deeply in love and well matched. Li Mengjue possesses the dignity and elegance of a real lady, while Xie Jingshu is considerate and gentle despite having limited mobility. But who knew that the two were already harboring malicious intentions towards each other and plotting against each other. Li Mengjue is actually a scout under the Suoming Sect, who infiltrated the Huachao Tower to investigate the "Tianshu Case". Likewise, Xie Jingshu is concealing his identity as a Northern Marquis and pretending to be a wealthy businessman and playboy. Until one dark and stormy night when the two of them looked at each other with smiles on their faces and Li Mengjue gives herself away. The couple, who has been to pretending to be loving, instantly sheds their last layer of disguise. However, at that time, the frequent homicide cases and clues all point to the past of the massacre case and Tianshu case. Driven by the reality of exploring the same goal, the two form a brief alliance and embark on the journey of searching for "Shortstalk Monkshood Root" to capture and subdue traitors with Lu Xi'er, Jing Yan, and Liu Yu'an…