Hong Kong action-star Louis Koo returns as William Luk, an investigator with the Independent Commission Against Corruption (ICAC), in this action-thriller directed by David Lam. In this fifth and final film in the "Storm" series, William will investigate a case in the Immigration Department which links it to a Thai human trafficking ring. ICAC首席调查主任陆志廉（古天乐饰）与总调查主任程德明（郑嘉颖饰）共同调查走私贪污案，却意外发现了另一起涉及人口贩卖的海关贪腐大案，该案与恐袭集团首脑King及其幕后指使人肖卓亚（谢天华饰）有关，并牵涉多名香港海关高层领导。 陆志廉带领ICAC反贪小队介入调查跨国人蛇贪腐案后，牵涉其中的海关高层人员接连出现意外。黑恶势力头目肖卓亚暗使手段令案件陷入僵局，金钱交易、恐怖威胁、妥协包庇等重重阻碍不断给陆志廉制造难题。此外，受邀到香港并被JFIU廖保强（张智霖饰）秘密保护的亚洲首席大法官庞爱玛（宣萱饰）、海关总署管辖程非熊（黄宗泽饰）似乎也牵涉其中，几方阵营互相试探、麻烦频出使局面混乱不堪