A paramilitary group who call themselves the ""Posse Magistratus"", have been the prime suspects for a series of bank robberies, and one particulary involving a heavily-modified World War II fighter plane. In order to track down this plane and stop the whole game, Chaney and Wonderlove attempt to track it down, based on various aerial police sightings. When accomplishing this, Chaney spots gun mounts on a plane that they performed an unauthorised thermograph upon, and results in not in the state of valid evidence to charge the Sheriff who owns it for the state-threatening operations. However that same day, the same World War II figher plane attacks them, and ends up being shot down by Chaney in Blue Thunder. To posess reliable and sufficent evidence to charge the ''Posse Magistrates'' of the crimes they have took out, Ski goes undercover as a mechanic, but it isn't long until Chaney and Wonderlove discover that the group plan to kill one of the cities' main councilmen at the Queen Mary s

Aggie Mills, an former flame of Chaney's who he knew back in the Vietnam War, comes for help via the FBI to distort a much-growing drugs & gun smuggling ring, extending to more places than just Los Angeles. When the first operation is not a success, and turns out to be a smokescreen, Bubba and Ski are assigned to go undercover as truck mechanics, but they also accidentally discover that Aggie Mills is not all what she says she is, and happens to be associating with the man in-charge of the whole operation, Harold Longstreet. When Bubba and Ski are caught red-handed while placing a radar receiver on one of the trucks, in order for Chaney and Braddock to know where the drugs and the weapons are being ferried from, its a race against time for Chaney and Wonderlove to save their two crew members, and prevent Longstreet and Mills from getting away, unconvicted.

Chaney's arch rival is given control of Blue Thunder after Chaney is reassigned for breaking off a drug stake out in order to pursue kidnappers