日本秘密警探滕堂受命到港铲除大毒枭李占美，他佯装贩毒打入匪巢，将李的三个儿子击毙。此时，香港皇家缉毒警官朱丽娅与助手泰迪获悉李占美与日本黑帮将进行毒品交易，亦展开调查。李占美为报子仇，派冷面杀手齐玄章杀死泰迪，并追杀滕堂至日本。朱丽娅追踪调查亦来到日本。于是，一场生死厮杀顷刻展开……

The Yakuza of Japan has infiltrated the universities of Hong Kong and are conducting illegal activities such as underground bare knuckle fights,gambling and drugs. Hong Kong Police team up with the Japanese Secret Service to bring down the ruthless gang but their agents always seem to wind up dead. As a last resort they have a female detective (Sibelle Hu) infiltrate the organization in order to bring them down.