The movie opens with title and credits and the Mitchell theme over stills of Mitchell (we will see this was the death of one of the Dune Buggy drivers later in the movie). It is late evening at the Walter Deaney lavish residence. No one is home and a burglar (John Ashby) breaks in through the French door to the study. Enroute home in his limo is Walter Deaney (John Saxon) and friends: two hookers and a public official are heading back to the house to continue the party. The burglar steals some silverware and looks over the gun case as the limo pulls onto the long driveway to the house. The blonde, Helena Jackman (Vicky Peters) and brunette, Prudence Lang (Carole Estes) hookers are left in the living room while Deaney and Don Townsend (Bill Sullivan) go to get something in another room. Deaney spots a light and hears the burglar in the study. Rather than call the police as Don suggests, he decides to take matters into his own hands. He sets a trap and gets a gun from a hallway drawer. When the burglar comes into the hallway to investigate, Deaney shoots him in the chest, killing him.A patrol car, carrying Mitchell (Joe Don Baker) in the backseat, responds to a police call at the Deaney residence. When they arrive, a private security patrol walks over to greet them. Mitchell joins the two patrolmen in the investigation. Deaney explains to the patrolman what happened. We see a firearm next to the body of the burglar. Mitchell picks up the hand gun with a pencil and places it in a plastic evidence bag. He asks Deaney if all the guns in the case are loaded. He pulls one from high in the case and check it and notices that Don and the two hookers are leaving. Mitchell activates the gate and closes it before the car can leave the property. He trots out to the limo while Deaney makes a phone call. The crime lab has arrived and tapes off the body and photographs the scene. Mitchell resumes his examination of the gun case contents.It is Christmas time and Police Chief Albert Pallin (Robert Phillips) enters the station. Mitchell is waiting for him in his office. The two men don't like each other. Mitchell has refused to sign the report on the death at the Deaney residence. Mitchell suspects Deaney is lying and that the death of the burglar was murder. Pallin warns Mitchell not to bother Deaney and to see Det. Aldridge (Buck Young) for his next assignment. Mitchell must watch one James Arthur Cummings (Martin Balsam) on a 24-hour surveillance. Det. Tyzack (Rayford Barnes) takes Mitchell to the Cummings residence and briefs him. He tells Mitchell that Cummings specializes in the import of stolen merchandise, and this week it is Heroin from Mexico: a full kilo. Mitchell vows to get both Deaney and Cummings, but Tyzack disagrees, "No way, you don't get neither." Mitchell gets in his car and waits for Cummings to come home. He doesn't have long to wait. Benton (Merlin Olsen) is Cummings' bodyguard and driver and pulls up and opens the car door for his boss. Mitchell trots up the driveway and introduces himself. Cummings dismisses the cop telling him, "Benefit's not due until January, son. Make an appointment, son, and have your chief give me a ring." Benton tartly adds, "No salesmen at this entrance." Mitchell walks back to his car to begin a long day. He lights up a cigarette. He empties out the ashtray as Benton watches from the house. Cummings approaches the driver's open window and asks, "All right. Now what do you want?" Mitchell asks about Mistretta and the Heroin shipment from Mexico. Cummings denies any knowledge and warns Mitchell about falling rocks. At midnight Mitchell drives to the Deaney home and Cummings calls Mistretta. A short time later Salvatore Mistretta (Morgan Paull) picks Cummings up at his home. They drive and talk. Cummings wants the dope shipped somewhere else. Mr. Gallano apparently approved of both the shipment and using Cummings' facilities without informing Cummings. Mitchell calls in to report he is at the Deaney residence and he is going inside unarmed. He makes entry the same as the burglar and notes he couldn't reach the handguns, if like the burglar, he was only 5'4" tall. Deaney is home and catches sight of the detective. A car headlight reveals Deaney and Mitchell runs back to his car. Mitchell returns to headquarters and he and Tyzack are going through the file room. Chief Pallin enters the room and orders Tyzack out. Pallin explains the Feds have been investigating Deaney and his trade union activities, so leave him alone. Mitchell returns home and is reviewing the Cummings file when someone comes to the door. It is Greta (Linda Evans), a very high priced hooker. She introduces herself as Mitchell's "new friend". He invites her in and offers her a drink. He manages to spill a beer on her legs. She explains that she is a Christmas present, but she won't tell Mitchell who is paying. Mitchell empties her purse and finds nothing but her ID. She leaves.The next day, Mitchell follows Cummings to the park. Cummings meets with Tony Gallano (Harold J. Stone) and again makes it clear he will not participate in the Heroin shipment. The short meeting ends and Mitchell follows Cummings car. Cummings stops and gets out to talk to Mitchell. He makes it clear he does not want to be bothered by the policeman. Assuming Mitchell would say no, Cummings and Benton arrange for a reception on a dirt road. An orange Mustang, driven by Benton's friend (Alan Gibbs) runs Mitchell off the road destroying Mitchell's car. Mitchell does manage to get the license number. He intends to deal with this person on his own terms.Cummings calls his friend Rudy Moran (Sidney Clute) in Las Vegas. He explains the situation, hoping for a little assistance, but Rudy tells Cummings, "What the hell are you calling me for? If Gallano's involved, I don't want any part of it." Mitchell picks up a new car and sees Cummings parked near the station. He drives up and parks next to a yellow Plymouth with three men inside. Mitchell gets out and walks over to the deli where Cummings is buying some food. He steps on Benton's foot on the way. As Cummings gets back into his car, the yellow Plymouth drives by and snaps the back door off the Lincoln. Mitchell walks back to his car and gets a call on the details about the Mustang driver. Mitchell drives over to the address and waits. He spots the driver pulling the battered orange car into the garage. Mitchell pulls up and gets out of his car. Before the man can retrieve a weapon from the passenger's side of the Mustang, Mitchell grabs him, hits him twice, and then kicks the door shut on the guy's hand. The man screams in pain, and Mitchell tells him, "Shut up, you'll wake up the neighbors." He takes the man's gun and leaves.Mitchell is at his desk at the station reviewing pictures of the Cummings case. Aldridge demands Mitchell bring in at least one man tailing Cummings. Cummings is out playing golf, Benton is acting as caddy. Mitchell watches from his car. A man from the yellow Plymouth gets out and approaches Cummings. Mitchell gets out of his car to observe. He talks to the man and is brushed off. Edmondo Bocca (Duffy Hambleton) runs towards Cummings, so Mitchell shoots him in the leg. He disarms the bleeding hood and hands the man's gun to Cummings. He tells Cummings, "I've got to go call headquarters." The two men in the yellow Plymouth observe the scene and then drive off. Aldridge confronts Mitchell outside the police station. Mitchell reminds Aldridge he wanted the man for two weeks and no bail and got it.Mitchell joins Cummings at his home for dinner. Benton acts as cook and butler. Cummings tries to impart some advice, but Mitchell asks about the Heroin. Cummings does volunteer that Bocca works for Mistretta. Cummings and Brenton get into an argument over the cold coffee. Mitchell drives home and gets beaten up by the two men in the Plymouth working for Mistretta. A night with Greta helps. Mitchell again asks Greta who is paying her and she refuses to answer. Mitchell tells her that he just wants to know who is paying her. She responds, "So why does that bother you, you're not paying for it...You couldn't afford me...$1,000 a night." Greta makes coffee and Mitchell again goes through her purse. He finds marijuana and he arrests her after she accuses him of being a crooked cop. He hands over the bag of grass to the Desk Sergeant (Jerry Hardin) and waits for her booking. Mitchell tells Greta, "It's only a $500 fine. At a $1000 per night, you're still ahead." "Oh, you're a mean bastard, Mitchell," she tartly replies. "I had a clean record in this town." Mitchell proudly confirms for the Desk Sergeant that he enjoyed her company, and then leaves the building.The next day, Mitchell is still on surveillance. Greta is parked behind him. Cummings tells Benton to invite Mitchell into the house. Cummings comes to the point, "I want to put you on the payroll." He concedes he needs help, "I want to buy your services." While Mitchell takes notes of the bribe, Greta bangs into Mitchell's car. She writes "Bastard" on the windshield with her lipstick. Cummings continues, "It could be open, cash, or subtle just like you take it from other people." On the subject of the hooker, Cummings notes, "She's too expensive, you can't afford her on a policeman's salary. Now someone's picking up the check, who could that be?" Mitchell tells Cummings it is him, but Cummings corrects the detective, "No, I don't. I don't pay for your whores, Mitchell." Mitchell asks, "Then who is?" Cummings laughs and responds, "You mean you don't know? You're a cop, and you don't know?" Mitchell storms out of the house and drives over to see Deaney. "I knew you'd call sooner or later," Deaney tells Mitchell. Deaney admits he admires Mitchell and adds, "How's the broad?" He offers to set up a company and transfer property with a $75,000 profit for Mitchell. Mitchell responds, "I'm gonna bust you for the murder of the Mexican, or die trying." Deaney warns Mitchell that that would be a big mistake.At the Indian Dunes Motor Recreation Park, Mitchell follows Cummings into the lot. Deaney is driving a Dune Buggy and talks to Cummings and suggest murder as a solution to their mutual problem. The limo departs and Mitchell follows. Cummings gets out of his car and sits in Mitchell's car. He offers Mitchell Walter Deaney, but Mitchell counteroffers that he will get Cummings first, and then he'll get Deaney on his own. Benton pulls a gun and takes Mitchell's gun. Cummings and Benton drive off. Cummings explains to Benton that if Deaney kills Mitchell, then Cummings will have more cops protecting him from Mistretta. They drive to the track and Mitchell gets stuck in the mud. He gets out and is soon menaced by Deaney in one of two Dune Buggies. They toy with Mitchell, who is on foot. Mitchell grabs a rock and kills one driver who got stuck. Mitchell gets in the Dune Buggy and goes after Deaney in the other. Deaney manages to flip his vehicle and it bursts into flames. Mitchell gets out and stares at the burning wreckage. He lights a cigarette and watches.Mitchell heads home for the night. The next day he is driving back to the Cummings residence. A radio broadcast announces the death of Walter Deaney. Mitchell honks the horn and Cummings comes to the window. A little boy (Todd Bass) approaches the car on a skateboard. He annoys Mitchell to the point where Mitchell tells the kid to piss off and go to hell. Cummings confronts Mitchell at his car and asks Mitchell why he hasn't been arrested. Mitchell tells Cummings he wants the whole crew, Mistretta, Gallano, and the Heroin. Cummings invites him in to the house and tells him what happened with the shipment. He offers to set up everything and hand it over to Mitchell, but he only gets the Heroin and Mistretta. Cummings emphasizes that he is not part of the deal. Mitchell agrees and acts as chauffeur and drives to the docks in Long Beach. The Kef Falcon has unloaded and a customs officer (Rob Narke) wheels a steamer trunk out to the waiting car. The Rich Old Lady (Lillian McBride) signs for it. Mitchell loads the case into the trunk of the car and drives off. They are observed by Benton who calls Cummings from a phone booth. Cummings then calls Mistretta and tells him about Mitchell and the consignment. He plans to take his boat out and knows Mistretta will kill Mitchell. He thinks he's solved his problems. Cummings makes one final call to the police. He reports that Mitchell will be going to see Mistretta and might need some help. Mitchell stops the Cadillac and checks for the heroin in the trunk. He tells the old lady that it is just chalk and she should just walk away from the whole mess. He concludes that Cummings is double-crossing Mistretta and Gallano. Before he drives off, Mitchell stuffs a rag into the gas filler tube on the car. He prepares the car as a bomb if need be. He then drives up to Calabasas and his rendezvous with Mistretta.Cummings and Benton get on the boat and pull out to sea. They are heading to Mexico. Mitchell drives to Mistretta's home. Mistretta and his henchman greet Mitchell. Mitchell feigns surprise at the double-cross. Mistretta reveals that he is going to kill Mitchell and put him on Cummings' boat. Mitchell manages to blow up the car and escape Mistretta and his men, at least initially. A police helicopter provides Mitchell a gun and he kills Mistretta and his three men. The helicopter pilot (Charles A. Tamburro) and the officer (Gary Combs) fly Mitchell to Marina del Rey and land so Mitchell can talk to the Harbor Master. They depart and head south for Mexico looking for the Cummings boat.The officer explains they have a fuel issue and if the boat crosses into Mexican waters they cannot arrest them. Mitchell asks about the large yellow tank they are carrying. The officer ties the rope to the tank and winch. Mitchell intends to use the tank as a battering ram on the boat. It works and Mitchell is able to distract Benton and Cummings long enough to drop down on to the boat. Mitchell manages to dispatch Benton with a boat hook. He tosses Benton's body overboard. He disables the engine. Cummings tries to make a final plea to Mitchell with a half-million dollar bribe. In a scene right out of Key Largo, Cummings feigns disarming himself and surrendering, but Mitchell is in no mood for an arrest. When Cummings turns to face him, armed of course, Mitchell drops him to the deck with a rifle bullet to the forehead.That night, a dead tired Mitchell goes home. He thinks his place has been burglarized and enters with his gun drawn. Greta is in his bed sleeping. He pulls her out and searches the apartment. They are alone. He asks how she got in. She shows him a key. Mitchell is horrified by the mess in the kitchen. He asks her to leave. He takes a shower while Greta cleans up the kitchen. He goes to bed, and Greta asks to join him. He sarcastically chides her, "What for? Nobody paying you this time." He smells marihuana, "That's grass." He finds a roach in the kitchen trashcan and grabs her and tells her to get her coat. He intends to arrest her again. We close with a freeze frame of Mitchell dragging Greta out of bed. Closing credits roll with the Mitchell theme playing.
Output: Question: Who does Cummings double-cross?, Answer: Bocca