曾混迹黑社会的印度裔男子维路出狱后，一心过回正常人生活，可惜人在江湖，身不由己。他最疼爱的弟弟跟随当年好友混入黑道；曾经的老大黑摩利据说也返回香港，图谋杀害机动部队陈督察；警官肥棠（林雪 饰）则隔三差五找到维路了解线索。维路不胜其扰，却又无可奈何。 　　另一方面，香港油尖旺鱼龙混杂，各方势力暗流涌动。森（任达华 饰）和May（邵美琪 饰）所率领的机动部队一面要平息黑道势力的争斗，同时还要四处追查黑摩利雇用的刀手。最终形势将朝何方发展？As rumors circulate that the long-disappeared Indian gang boss known as Black Molly is about to return to the underworld, Tactical Unit officers Sam (Simon Yam) and May (Maggie Shiu) are prepared to tackle the ensuing troubles. Molly's right-hand man Velu decides to quit the gang after serving a prison term, but his former partner Sonu feels betrayed, and vows to kill him. Meanwhile, Sonu is driven down the path of no return when he gets assigned the job of assassinating Chief Inspector Chan, Sam and May's superior.