Danny Ciello est un policier de l'unité des enquêtes spéciales (SIU - Special Investigations Unit), un service de la police de New York (NYPD - New York City Police Department) s'occupant de la lutte antidrogue. C'est l'élite de la police, à qui aucune faute n'est pardonnée par les autorités judiciaires et fédérales. Ces dernières confient à Danny la mission de piéger un avocat véreux. Mais Danny comprend bientôt qu'il est manipulé pour faire tomber des collègues accusés de corruption, alors que les têtes dirigeantes associées à la mafia ne sont guère inquiétées.
Immigration enforcement agent Smith (Jack Nicholson) lives in California with his wife (Valerie Perrine) in a trailer. She persuades him to move to a duplex in El Paso shared by her friend and border agent Cat (Harvey Keitel). She opens a charge account and starts to purchase expensive items like a water bed as she tries to build a dream home.
On the U.S.-Mexico border, a time bomb is planted in a car. A man and woman enter the vehicle and make a slow journey through town to the U.S. border, the woman (Joi Lansing) insisting that she hears something ticking. Newlyweds Miguel "Mike" Vargas (Charlton Heston), a drug enforcement official in the Mexican government, and Susie (Janet Leigh) pass the car several times on foot. The car crosses the border, then explodes, killing the occupants. (The cut to the exploding car is the first one in the film, the single-camera opening sequence lasting nearly three and one-half minutes.)
In The Bronx, the Lieutenant drops his two sons off at Catholic school. After they leave the car, and before he drives to work, the Lieutenant takes a few small bumps of cocaine. His first case is a double murder. He wanders away from the scene to get some coffee, and across the street, he watches a petty thief rifling through the trunks of parked cars, which the Lieutenant ignores. He approaches a group of drug dealers, who run off as he approaches. The Lieutenant follows one dealer into an apartment building and up the stairs. The dealer waits for him in the hallway, and the Lieutenant gives him a bag of drugs from a crime scene. The Lieutenant quickly smokes some crack, and then sets aside a portion of the drugs for himself. The thief promises to give him the money he makes from selling the drugs in a few days. At an apartment, the Lieutenant gets drunk and engages in a threesome with two women. Meanwhile, a nun is raped in a church by two young hoodlums.
Officer Dave Brown (Harrelson) has two ex-wives who are sisters (Anne Heche and Cynthia Nixon), and he cheated on both. Brown has a daughter from each marriage which creates conflict at home. Dave also has contentious relationships with his children. However, the film starts with his other home, which is the beat. Dave patrols streets occupied by gangs, and he creates problems for himself with increasing severity. Dave forcibly obtains a confession out of a convenience store thief. Later he is caught on tape beating someone almost to death. The beating is still playing on television when he's involved in a suspicious shooting. These incidents get Dave in trouble with an already beleaguered police department, and he faces either sanctions or forced retirement. Dave tries to talk his way out of trouble with an assistant district attorney (Sigourney Weaver). Dave realizes that his superiors are less concerned about what he has done but more concerned about the predicament he has created by getting caught.
Chloe, a single mother living with her daughter Sophia, operates a motel. Topo is a blind man traveling cross country in a Jeep with his associate John. They stop by Chloe's motel, when John hires prostitute Gwen, and convinces Topo to stay the night. When Gwen is entertaining John, an argument has John fatally shooting Gwen, waking Chloe up. Chloe investigating finds Gwen and John dead.
In the South, Sampson and the local Preacherman plan to bust out their friend Randy from prison. As they rush to the prison, the two are stopped by a roadblock and have a shootout with the police. Meanwhile, Randy and another cellmate named Pappy escape from inside the prison and wait for Sampson and the Preacherman to help them get out. While waiting for them, Randy unwillingly listens to Pappy tell a story about three guys that resemble Randy and his friends. Pappy's story is told in animation set against live-action background photos and footage.
Dans les années 1980, René Boisrond, inspecteur en poste au commissariat du 18e arrondissement de Paris, mène une vie bien tranquille, entre sa concubine Simone, une ex-prostituée, et son travail qui consiste essentiellement à encaisser pots-de-vin et commissions occultes en tous genres, lui permettant d'assouvir sa passion pour les courses hippiques.
François et René forment une équipe de ripoux depuis déjà 5 ans quand François, qui envisage de passer l'examen de commissaire, souhaite redevenir honnête. Mais lorsqu'il remet à une boutiquière volée l'argent dérobé, celle-ci, en raison d'une vieille rancune envers René, les accuse aussitôt du forfait. Les deux flics sont alors suspendus et remplacés par les inspecteurs Brisson et Portal, censés être de véritables modèles d'intégrité. Mais les apparences sont trompeuses.
Stanislas Borowitz is a divisional commissioner from the IGPN (Inspection Générale de la Police Nationale) who uses particularly expeditious methods to counteract the "ripoux" (French term for "corrupt cops"). Sent to Nice to struggle against the Mafia and enquire on a murder of a notoriously corrupt commissioner, he changes his identity into a thug named Antonio Cerruti to trigger a gang war between the two biggest local sponsors, Théodore Musard ("l'Auvergnat") and Achille Volfoni ("le Corse"), and discovers a police organization with the mafia of the town. But the corrupt police inspectors Rey and Massard, on the pay of Volfini, absolutely want to harm him.
Jean-Baptiste et Magdaleine sont un couple marié de Haïtiens qui travaille dans une plantation de canne à sucre en République Dominicaine. Quand leur bébé meurt de faim, Magdaleine décide de revenir en Haïti.
Comme il le souhaitait dès l'époque de sa rencontre avec René Boirond, François Lesbuche est devenu commissaire à l'IGS, là où lui et René avaient été embauchés à la fin du deuxième opus. Malgré son grade et sa volonté d'être incorruptible, il n'hésite pas à rejouer les ripoux pour aider son vieil ami René, retraité reclus sur sa péniche. Impliqué bien malgré lui dans une affaire de blanchiment d'argent, René qui a accidentellement perdu le magot qui lui avait été confié est poursuivi par les commerçants chinois de Belleville. Avec l'aide d'un ami chirurgien, Albert, René change d'identité et devient Jean Morzini, un patient de la clinique d'Albert récemment décédé. Il reçoit alors la visite d'une certaine Maud qui lui remet les instructions pour le casse d'une banque que Morzini avait prévu de cambrioler ; et de la fille du vrai Morzini, Marie, qui n'avait jamais vu son père et croit que c'est René. Simultanément, François prend sous sa tutelle un jeune stagiaire, Julien, filleul de son patron, qui s'éprend de Marie.
In the not very distant future, where crime has been completely eradicated, a group of crooked cops look to dispose of a body that one of them accidentally shot.
A sa sortie de prison, Sam tente de se réinsérer mais il est vite rattrapé par le milieu et sombre peu à peu dans un engrenage criminel. A travers les yeux de son fils, il perçoit une lueur d'espoir.