In the Bronx borough of New York City, in the 1970s, undercover policeman Terry Noonan and Italian-American gangster DeMarco meet Nick Richardson and another undercover cop for what appears to be a late-night drug purchase. When Nick attempts a robbery, Terry Noonan draws his gun and shoots the two “dealers” with blanks, then hurries DeMarco away, so that he thinks the robbers are dead. DeMarco drives back to his Italian neighborhood, and Terry takes the subway to “Hell’s Kitchen,” an Irish neighborhood in Manhattan. At a bar, Terry sits down with Jackie Flannery, an old friend he has not seen in years. Jackie invites Terry to his rooftop apartment to drink and discuss old times. Jackie explains that the neighborhood has gentrified in the ten years Terry has been away, and nobody calls the neighborhood Hell’s Kitchen anymore. However, the Irish gang still runs things, and the last time a murder witness stepped forward, police found his head in a clothes dryer. When Terry complains that his latest drug transaction with DeMarco went awry and forced him to kill two dealers, Jackie blames him for trusting Italians. Jackie’s own brother, Frankie Flannery, has joined forces with Italian mobster Joe Borelli, and Jackie is unhappy with the arrangement. He jokingly displays two severed hands he keeps in the freezer, in case he needs to leave fingerprints on a weapon. When they return to the bar, Jackie’s sister, Kathleen “Kate” Flannery, comes in. Kate is surprised to see her old lover, Terry Noonan, after so many years, and they make vague plans to get together. However, Kate has forsaken the neighborhood and moved uptown, where she works at the Regent Hotel. Later, Terry and Jackie find another old friend, Stevie Maguire, being hassled by two of Italian mobster Jimmy Cavello’s enforcers over an $8,000 gambling debt. Jackie and Terry beat up the two and give Stevie his money back, so that he can go to the racetrack. When Terry Noonan asks about a job with Frankie Flannery’s gang, Jackie takes him to New Jersey, where his brother lives with his wife and kids. Frankie has already heard about the two drug dealers Terry “dropped” in the Bronx, so he is interested in using Terry on some jobs. However, after Terry Noonan leaves, Frankie orders his right-hand man, Pat Nicholson, to check out Terry’s story. Terry accompanies Jackie on an arson job, but as he witnesses Jackie’s manic disregard for safety, Terry realizes his boyhood friend is unstable. Later, Terry goes uptown to Kate Flannery’s workplace and tries to rekindle their former relationship, but she wants to escape the criminality of her family and neighborhood. Meanwhile, Pat Nicholson finds DeMarco in a bar, puts a gun in his face, and takes him for a walk. At 2 a.m., Jackie Flannery awakens Terry for a “job” with Frankie, Pat Nicholson, and Stevie Maguire. They carry cases of liquor into a bar and demand that the owner, Raferty, pay for the shipment. When Raferty resists, Pat Nicholson beats him up and Jackie smashes bottles behind the bar. Stevie Maguire intervenes on Raferty’s behalf, but Pat Nicholson hits him, and Terry in turn hits Nicholson. Outside, Frankie Flannery berates his gang because their dissension shows weakness, and warns Terry never to “go against” him again. From now on, they have to impress their new Italian partner, Joe Borelli. Afterward, Terry goes to Kate’s apartment and awakens her for a heart-to-heart talk. The next day, Joe Borelli summons Frankie Flannery to his restaurant. He informs Frankie that Stevie Maguire’s $8,000 debt to Jimmy Cavello shows disrespect, but he does not want to send his enforcers into Frankie’s neighborhood to solve the problem. Frankie promises to take care of it. That night, Pat Nicholson pulls Stevie out of a bar and, in the alley, Frankie cuts his throat. Terry Noonan is sleeping with Kate when Jackie Flannery telephones to tell him that Stevie is dead. Terry, Jackie, and Kate watch police haul Stevie’s body out of the East River. Although Jackie is determined to find out who killed Stevie, Kate becomes angry because Jackie’s friends are always getting hurt for not paying debts, yet he never does anything about it. She berates Terry for returning to Hell’s Kitchen. When Terry accompanies Jackie to the borough of Queens for the funeral of a neighborhood policeman, he recognizes Nick Richardson, the man he “killed” in the Bronx, as one of the pallbearers. Afterward, at a bar frequented by police, Terry Noonan tells Nick that if DeMarco saw him walking around, it would expose their undercover operation. Nick informs Terry that DeMarco was murdered. Later, Terry meets Nick on an empty subway car, and Nick speculates that Frankie Flannery killed Stevie Maguire to impress Borelli, and killed DeMarco so that the Bronx shootings of the two dealers could not be traced back to Terry and, by implication, Frankie’s gang. Terry tells Nick he wants “out” of the operation, because the guilt of betraying his boyhood friends is making him drink too much. He ran away to Boston, Massachusetts, and became a cop to escape his past, but now the neighborhood has pulled him back. Nick reminds Terry that they must stop Frankie Flannery before his new business relationship with Joe Borelli gets many people killed. At a Hell’s Kitchen bar, Frankie warns his brother Jackie that under the new rules, they cannot kill anybody without Borelli’s permission, even though Borelli’s men killed Stevie Maguire. Jackie, frustrated and enraged, beats up an innocent customer and smashes bottles. Frankie tells Terry Noonan to keep an eye on Jackie, but then orders Pat Nicholson to keep an eye on Terry. Late that night, Kate and Terry find a drunken Jackie Flannery mourning Stevie’s death at a neighborhood church. When Terry and Kate return to her apartment and begin making love, he confesses that he is “a Judas cop.” The next day, Frankie Flannery sends Terry Noonan to collect a debt from Finn, an old man who lives in poverty. Finn recognizes Terry as “Eddy Noonan’s boy” and scorns him for working for the Flannery family. He warns Terry that the Flannerys will eventually turn against him, and hints that he witnessed Pat Nicholson taking Stevie Maguire out of Matty’s Bar on the night he was killed. Later, when Terry goes to Matty’s Bar, Nicholson follows and telephones Frankie Flannery, who wonders if Terry is asking around about Stevie Maguire. Inside the bar, Terry forces Matty to confess that Nicholson pulled Stevie out of the place on the night he was killed. After Terry leaves, Nicholson shoots Matty. Frankie Flannery visits his sister Kate at the Regent Hotel and informs her that she is mistaken if she thinks Terry Noonan is any better than her brothers, because he killed two drug dealers in the Bronx a couple weeks earlier. Later, when Kate goes to Terry’s apartment to ask about the shooting, he explains that it was a set-up. Fearing Terry will destroy her brothers, Kate orders him to stay away from her and storms out. Jackie Flannery sits in a bar as Jimmy Cavello and two of his men arrive and invite Jackie Flannery to have a drink. Jackie shoots all three and walks out. When Borelli telephones Frankie Flannery to demand a meeting concerning his out-of-control kid brother, Frankie fears retaliation. He arranges for Terry, Jackie, and others to arm themselves and wait at an address in Little Italy. Accompanied by Pat Nicholson, Frankie meets Borelli at the Fanella Cafe. The Italian mobster insists that if Frankie cannot kill his brother, it will be done for him. Frankie tries to use the telephone, but Borelli tells him to do it later. Nearby, Jackie gets antsy when Frankie does not telephone. He leads his men to the café, and as they approach, Borelli and his men step outside. However, before Jackie can open fire, Frankie puts his arms around Joe Borelli, forcing Jackie to retreat. Later, Frankie tells Jackie that Joe Borelli is happy he shot Jimmy Cavello, because Cavello killed Stevie Maguire without permission. In fact, Borelli has hired them to knock off a couple troublemakers in Battery Park. Jackie later tells Terry Noonan he has a job at eleven that night, but will meet Terry afterward at the club. When Terry mentions he heard that Frankie put the hit on Stevie, Jackie explodes, pulls a gun on him, and orders him out. Terry telephones Nick and tells him to be at Battery Park at eleven. Jackie later apologizes and asks Terry to accompany him to the job, but he drives to Pier 84 instead of Battery Park, revealing at the last moment that the location has been changed. As Terry hides and makes a call from a telephone booth, Frankie Flannery arrives and shoots his brother with a silencer-equipped gun. As Frankie pulls away, Terry finds Jackie dead. He tells Nick Richardson he is quitting his undercover job. At Jackie’s funeral, Terry tries to soothe Kate, but she laments that she did not warn her brother that Terry is a cop. Terry informs Frankie Flannery that he was on Pier 84 when Jackie was killed, and as he leaves the mortuary, he gives Frankie his Boston police badge and identification. Frankie issues a hit on Terry Noonan. At Kate’s apartment, Terry explains that he wanted to spare her family when he took the undercover assignment, but events worked against him. Unmoved, Kate leaves for a dinner date. Terry sleeps in Grand Central Station, while Frankie Flannery’s gang hunts for him. The next day, during the city’s big St. Patrick’s Day parade, Terry walks among the Irish marchers, unaware that Kate Flannery is nearby, watching the parade. He goes to Frankie’s bar and kills Pat Nicholson, Frankie Flannery, and three other men in a shootout that leaves him wounded.