Dragon has been an infiltrator in Hung's Hong Kong triad gang for many years. After a failure of a recent negotiation by Dragon with the other three local triad gangs on behalf of Hung makes the latter suspicious of Dragon's identity. Hung sets to wipe out every undercover cop in his gang and as a result many cops are caught and wiped out. Sensing the danger, Dragon requests to put an end to his undercover career from his captain, Cheung. However, Cheung sends Dragon to Mainland China to infiltrate a business of "Special Identity" trading instead. The business is run by Hung's best protégé, Sunny, who was Dragon's previous buddy in the gang. Cheung promises to reinstate Dragon's police identity in conclusion of the mission once Sunny's business breaks down. Dragon agrees, and joining him are local police officers Lei Peng and Fang Jing from the Mainland Chinese police force. But before they can get to Sunny, the latter suddenly vanishes leaving Dragon exposed and in great danger...