国民革命军北伐前，军阀割据地区法纪荡然；不肖嫖吏欺凌百姓，市井无赖鱼肉乡里，小人之行径可恶，小人之嘴脸则可笑。片中刘三麻子即小人之代表也。刘三由线民而成公安队员而至小队长，胡作妄为、丑态百出，东施效颦每令人喷饭。今日之社会自由而崇法与昔迥异，不容刘三等宵小存在。故本片采取喜剧方式，以博观众一笑。

With this film we tell the story of police tipster Polka Dots Liu, badge 369 but often jokingly called the Supremo. He entertains most of the times. Once, he brandishes a gun at a casino to stress a point. He wins the point and some credit, too. And he tries to chat up the barber's wife under the man's very razor. The barber gladly runs him out of town. The he pumps into a robbery and captures the robber by mistake. That's what he does when he gets his badge...