本片讲述了明国初年，因一名“编外巡警”范吉安为寻求转正机会，与“街溜子”小榔头联合制造假案，不料陷入老警长被害等多起连环凶杀案中。在警方的探查下，范吉安不仅晋升无望，他与小榔头的杀人嫌疑越发深重，接二连三的凶案彻底打破了狍子岭的安宁，二人历尽磨难，最终破解了连环凶案之谜并逮捕了真凶的故事。

民國初年，一名“編外巡警”範吉安為尋求轉正機會，與“街溜子”小榔頭聯合制造假案，不料陷入老警長被害等多起連環兇殺案中。在警方的探查下，範吉安不僅晉升無望，他與小榔頭的殺人嫌疑越發深重，接二連三的兇案徹底打破了麅子嶺的安寧，二人歷盡磨難，最終破解了連環兇案之謎並逮捕了真兇的故事。

In early Republican China, aspiring patrol officer Fan Ji'an and street hustler Xiao Langtou stage a fake case to secure a promotion. However, they become prime suspects in a series of real murders, including the death of a veteran police chief. As the investigation unfolds, they must clear their names and uncover the true killer before it's too late.