Three murder cases have occurred in the Shanghai French Concession, and remarkably, the three seemingly unrelated victims all share the same name 'Zhong Ming.' The killer is skilled in using highly toxic concealed weapons and joint-lock combat, with an extremely high psychological resilience, likely a cold-blooded assassin with exceptional skills. Inspector Zhong Lang (played by Lyu Liangwei) joins forces with Yu Shengnan (Li Ruosi), Kang Huasheng (Xu Liang), and Hong Xiaoya (Ma Cancan) to conduct a joint investigation, but initial results raise suspicion in Zhong Lang's mind. It turns out that many years ago, he had gone undercover in the gang 'Pan Long Tan' using the alias 'Zhong Ming,' and he instinctively believes the killer is targeting him. The investigation reveals that the killer is suffering from late-stage tuberculosis and, with little time left, seems intent on using his last remaining days to kill Zhong Ming as a personal vendetta, going so far as to commit indiscriminate murder. Following the leads, Zhong Lang indeed finds the cases are connected to a series of incidents from his undercover days. A deadly chase ensues, with a life-and-death agreement hiding in the shadows for the killer.