Hooker and Romano go after a customized van when it runs a red light. The van pulls over but when Hooker and Romano approach it on foot, it takes off. Hooker and Romano in hot pursuit by car are surprised when someone in the van begins shooting at them with a machine gun. Eventually, the van crashes but its two passengers escape. The driver is knocked unconscious and it's discovered that the van is full of firearms. Veteran cop Pete Benedict is soon on the scene, happily surprised to see Hooker -- partners when Hooker was a rookie. This is obviously a case of illegal irons, enough to arm every punk on this side of town. Meanwhile, in a custom body shop across town, a huge, behemoth of a man, Mountain, is furious with the two men who escaped from the van for losing the merchandise. Benedict, Hooker and Romano inspect the confiscated weapons and see that all the serial numbers have been filed away. Unfortunately, they can't get any information from the driver of the van because he's just died in surgery. Hooker puts pressure on a local bookie, Banty, to buy an illegal gun for him, one that can't be traced. Hooker and Romano watch as the transaction goes down. Sonny, one of Mountain's boys, delivers the goods to Banty and then Hooker and Romano go after him, nabbing him after a good chase. Hooker notices that Sonny has the same tattoo on his arm that the van's driver had and identifies it as the symbol of a bad motorcycle gang called the Demons that broke up years ago. On his way downtown to check out a lead of a former Demon owning a shop downtown, Hooker learns that Banty has been killed for helping him. Hooker and Romano arrive at Mountain's shop and provoke a fight, resulting in Mountain and his boys' arrests. Then Hooker turns to his D.A. friend to get him a search warrant on Mountain's place. Hooker raids the shop and this time he captures both Mountain and a gun with the serial numbers filed away. Treating the gun with acid to make the numbers appear, Hooker is stunned to learn that the gun was taken from the Police Property Room. Hooker follows this up at the plant where the gun was supposedly destroyed. There he discovers a huge gun smuggling operation run by Pete Benedict himself. After an emotional confrontation and a fight, Hooker arrests the man who was his mentor.