A routine traffic accident, the car of Raymond Lo, (Liu Qingyun), a well-known securities dealer in Hong Kong, was found to have been bugged. According to the police investigation, the bug was for military use. The Security Department intervened and after Chief Inspector Ho Chi Keung (Louis Koo) investigated, it turned out that the person who did the bugging was a discharged soldier, Szema Nien Cho (Daniel Wu). Thus began a series of chases between the police and the criminals, causing turmoil. Ho Chi Keung initially thought this was just a simple case of extortion.