Detective Sargent Jun Ma of the Serious Crimes Unit is precise and brutal. Determined to destroy his criminal nemeses Archer, Tiger and Tony, a gang of three powerful brothers, Jun Ma infiltrates their corrupt organization with the planting of a mole, Wilson. When Wilson's dual role is exposed, he becomes the last living witness to testify against Archer and now Jun Ma must battle to protect his partner from the murderous thugs to ensure they are put out of business permanently.