Plot
In Beverly Hills, an organised criminal gang led by the ruthless Karla Fry carries out a precision robbery of a jewellery store, leaving behind an envelope marked "A" containing a cryptic code. Captain Andrew Bogomil investigates the robbery with Detective Billy Rosewood and Sergeant John Taggart, but is suspended by the egotistical new police chief, Harold Lutz, in retaliation for Rosewood contacting the FBI for assistance, believing outside help undermines his authority. On his way home, Bogomil is lured into a trap by Fry, who leaves him with near-fatal gunshot wounds and a letter marked "B".
Learning of Bogomil's attack, his friend, Detroit police detective Axel Foley, travels to Beverly Hills to investigate. After examining expertly modified bullet casings recovered from the robbery, Foley visits a local gun club, where he meets Fry—who matches the description of one of the robbery's perpetrators—and learns similar casings were produced for the club's manager, Charles Cain. Furious that Cain used traceable ammunition, his employer, businessman Maxwell Dent, orders him to kill Foley. The assassination attempt by Cain's men fails, but Foley recovers a matchbook from which he lifts Cain's fingerprint.
Foley breaks into the gun club that night and discovers a set of coordinates, which lead him, Rosewood, and Taggart to the city depository, the target of the "C" and "D" robberies. They foil the heist before pursuing the perpetrators' armoured truck through Beverly Hills in a cement mixer, causing extensive collateral damage. Although the robbers escape, Foley, Rosewood, and Taggart trace the getaway vehicle to an event at the Playboy Mansion. Recognizing Fry from the gun club, Foley confronts her and Dent before they are all removed from the event.
Foley learns from Dent's accountant that Dent and Fry have applied for visas to Costa Rica. At the same time, Bogomil's daughter Jan discovers Dent's companies are in financial difficulty and that he has allowed the insurance to lapse on all of them, except for his horse racetrack, Empyrean Fields. Foley deciphers the "D" letter and learns it is signed "Carlos", the Spanish version of Charles. Realizing the letter was deliberately easier to decode, Foley deduces that Dent is framing Cain as the Alphabet robber. Dent sends Cain with Fry during the racetrack robbery. Afterwards, Fry kills Cain, making it appear that he was killed by a guard.
Lutz publicly announces that Cain was the Alphabet bandit and takes credit for the success. Foley notices red mud at the stables identical to traces found on Bogomil's running shoes. This leads Foley, Rosewood, and Taggart to Dent's nearby oil field, where Dent is using the $10 million stolen in the robberies to purchase weapons from arms dealer Nikos Thomopolis, intending to resell them in Central America for massive profit.
Foley, Rosewood, and Taggart engage Dent's men in a shootout and destroy the trucks carrying the weapons with explosives. Dent attempts to run Foley down, but Foley shoots him dead before being struck by the vehicle. Fry attempts to kill Foley, but is shot dead by Taggart.
As Dent's remaining associates attempt to flee, police reinforcements arrive and arrest Thomopolis and the rest of Dent's gang. Lutz and Mayor Egan also arrive; Lutz berates Rosewood and Taggart for their insubordination, but they finally stand up to him and prove that Dent was the mastermind behind the Alphabet crimes. Convinced of Lutz's incompetence, the mayor dismisses him for jeopardizing the investigation and mistreating his officers.
Following his recovery, Bogomil becomes the new police chief. As Foley prepares to return to Detroit, Mayor Egan telephones Inspector Todd to thank him for Foley's assistance, prompting Todd to angrily order him back to Detroit.
