In Shanghai in the 1920s, the protagonist Mo Xiaoyu was a manager who had just joined the family business after studying abroad. She encountered an accident during an important bidding event. The meal she ordered from the company was handed over to an intern, Cheng Han, who ate it. As a result, Cheng Han died of poisoning. Mo Xiaoyu was shocked and blamed herself, and vowed to find the real culprit. Her best friend Tang Xin worked together to help find the real culprit.
The first suspect is her assistant Li Yunlong, who is jealous of Mo Xiaoyu, but there is insufficient evidence. However, in order to prove his innocence, Li Yunlong joined the investigation. The second suspect was a waiter, but the personal information he provided was false.
During the investigation, Mo Xiaoyu discovered the secret of a corruption case within the company and was assassinated. Fortunately, codename Q took action in time and saved Xiaoyu.
Finally, in an elaborate plan, Mo Xiaoyu, Tang Xin, codename Q and others joined forces to bring the murderer to justice and seek justice for Cheng Han.
