Hong Kong Customs and Excise Department officers Chow Ching-lai and Cheung Wan-nam share a close mentor-student relationship. On a case involving seized smuggled arms, Ching-lai is sent to take part in a joint operation with Interpol to capture a reclusive arms dealer. However, Wan-nam makes a drastic decision that further complicates the case.

On the eve of the 1997 handover, violence is rampant as the British Hong Kong government has joined forces with the triads to cause chaos in Hong Kong. The gang leader, Lam Yiu-Cheong assigns his crony Ah Lok to take an important role in the destruction. But Lok harbours a secret – he’s an undercover policeman and he’s about to discover a political conspiracy that will shock the country to its core.