The irreplaceable monster detective Ma Xidao returns in style! Seven years after arresting a fugitive in Vietnam, Ma Xidao (Ma Dongxi) was promoted to the Seoul Metropolitan Investigation Team and formed a new police force to investigate a bizarre murder case in order to catch the criminal as soon as possible. During the investigation of the case, Ma Xidao discovered a new type of drug crime hidden under the case, so he decided to expand the scope of the investigation. The mastermind behind the drug case, Zhu Chengzhe (Lee Junhe), unscrupulously expanded this series of illegal transactions. At the same time, Ricky (Aoki Munetaka), the head of a Japanese organization specializing in drug distribution, also came to South Korea and was involved in the transaction case, which made the scale of crime expand day by day. In order to arrest the criminals, Ma Xidao will launch a thrilling anti-crime operation with his teammates.