During the reign of Emperor Huizong of the Northern Song Dynasty, General Ling Lushi colluded with Cai Jing, the traitorous minister of the dynasty, resulting in the corruption of the dynasty and the decline of the country's power. In order to fight against Ling Lok Shek, who is a powerful and vicious martial artist, Zhuge Divine Constabulary teaches Coldblood individual martial arts skills, and at the same time cultivates three other young men with great qualifications and potentials, namely Life Snatcher, Emotionless, and Iron Hands, who are trained to kill Ling Lok Shek by combining and dividing their martial arts skills. The four of them are appointed by Zhuge God as the "Four Chief Constables of Department Six" - Iron Hands in the East, Life Snatcher in the South, Emotionless in the North, and Cold-Blooded in the West - to safeguard the peace and tranquility of all places in the four directions.

北宋徽宗年间，镇远大将军凌落石与当朝奸相蔡京相互勾结，狼狈为奸，致使朝纲败坏，国势日衰。身兼武林大联盟副盟主的凌落石，更因觊觎武林盟主宝座，而趁盟主冷悔善过寿时，将其杀害，取而代之，冷悔善幼子冷血（蒋毅 饰）侥幸死里逃生，并为太傅诸葛神侯（岳跃利 饰）收养于狼窟中长大。诸葛神侯为对抗武功高强、阴险狠毒的凌落石，除个别传授冷血武功，亦同时培养另外三位极具资质潜力的血气青年追命（钟汉良 饰）、无情（朱磊 饰）、铁手（车仁表 饰）分别授与武功有成后，以分进合击方式，展开连串刺杀凌落石之艰巨任务。四人呗诸葛神封为“六扇门御前四方总捕” ——东方总捕铁手、南方总捕追命、北方总捕无情、西方总捕冷血，四人分别保卫着四方各地安宁。

北宋徽宗年間，鎮遠大將軍凌落石與當朝奸相蔡京相互勾結，狼狽為奸，致使朝綱敗壞，國勢日衰。身兼武林大聯盟副盟主的凌落石，更因覬覦武林盟主寶座，而趁盟主冷悔善過壽時，將其殺害，取而代之，冷悔善幼子冷血（蔣毅 飾）僥倖死裏逃生，併為太傅諸葛神侯（嶽躍利 飾）收養於狼窟中長大。諸葛神侯為對抗武功高強、陰險狠毒的凌落石，除個別傳授冷血武功，亦同時培養另外三位極具資質潛力的血氣青年追命（鍾漢良 飾）、無情（朱磊 飾）、鐵手（車仁表 飾）分別授與武功有成後，以分進合擊方式，展開連串刺殺凌落石之艱鉅任務。四人唄諸葛神封為“六扇門御前四方總捕” ——東方總捕鐵手、南方總捕追命、北方總捕無情、西方總捕冷血，四人分別保衞着四方各地安寧。