During the Vietnam War, soldiers Michael Jefferson and John Eastland are taken prisoner, but Michael overcomes the captors and saves John’s life. In present-day New York City, Michael once again comes to his friend’s rescue when John discovers members of the Ghetto Ghoul gang stealing beer from the loading docks where the men work. Later, Michael is assaulted by the Ghouls and left paralyzed. John breaks the news to Michael’s wife, Maria. After interrogating a member of the Ghouls while wielding a flamethrower, John learns the address of the gang’s clubhouse. Arriving at the hideout with a rifle, John finds the three men who mugged Michael partying with prostitutes. As the women flee, John kills one of the men and beats the other two then drags their bodies to the basement and leaves them to be eaten by rats. When Detective James Dalton arrives, he learns that one Ghoul survived. Meanwhile, mob boss Gino Pontivini, the owner of the dock and meat packing plant where John works, is informed that Congress is suspicious of the rapid increase in beef prices. Although an investigation is imminent unless Pontivini lowers his prices, he is reluctant to give up his lucrative racket. Following up on the Ghoul case, Dalton arrests Candy, one of the prostitutes, and she gives him John Eastland’s description. Visiting Michael in the hospital, John tells his friend that he avenged the attackers and confesses that the experience reminded him of Vietnam, where he felt no difference between right and wrong. John assures Michael that he has come up with a plan to provide financial support for Maria and their children. Later, John kidnaps Pontivini and hangs him above a meat grinder, threatening to reclaim the money he took in by exploiting men like Michael. Pontivini gives John his house keys and the combination to his safe. When John is attacked by a guard dog at the Pontivini mansion, he returns to the warehouse and lowers the gangster into the grinder. Meanwhile, Dalton visits the surviving Ghoul in the hospital and finds him unable to communicate, then takes Dr. Megan Stewart on a date. At the same time, a Times Square prostitute is abducted and tortured by two men. On the local news, the announcer reports Pontivini’s murder and reads a note from “The Exterminator,” who takes responsibility for the mobster’s death and states that more vigilante justice will follow. Concerned that the Exterminator’s actions will make the government look weak as elections near, two CIA agents plan to destroy him. Some time later, John is approached by the Times Square prostitute and he takes her to a hotel. When he sees her scars, she tells him about the Chicken Pimp, who punished her for refusing to participate in his child prostitution ring. John promises the girl that she will not be hurt again. John burns the Chicken Pimp alive, shoots his client and frees the teenage boy he holds captive. When Dalton arrives at the scene, he learns that the pedophile client was a New Jersey Senator. Back at his office, Dalton receives an autopsy of the recently deceased Ghoul and a phone message from CIA Agent Shaw. Before he can respond to Shaw, Megan calls. Dalton tells her that the Exterminator suspect is a former soldier based on Candy’s identification of his army-issue M-16 rifle. A footprint at the meat packing plant has been traced to hunting boots sold by a mail-order company and the police have isolated veterans from their clientele records. At a jazz concert in Battery Park, Dalton learns that Megan was an anti-war protester and reveals that he is a Vietnam veteran. Meanwhile, an elderly woman is mugged in Central Park by the Ghouls and John gives chase on a stolen motorcycle. He shoots one of the Ghouls dead at a stop light. When the others attempt to run him over, John shoots the driver and the car explodes and careens off a bridge. At the crime scene, Shaw introduces himself to Dalton and complains that the detective has been uncooperative. When Dalton demands to know why the CIA is involved with his case, Shaw warns that the Exterminator could be working with a foreign government to destabilize the United States during an election, but Dalton rebuffs him and calls Megan. While Dalton and Megan make love in a spare hospital room, John visits Michael and tells him that Maria has taken the money. He offers to disconnect his friend from his life support system and Michael agrees with two blinks of his eyes. An alarm sounds from Michael’s room and Dalton sees John enter the elevator. When Megan tells him that Michael’s respirator wire was cut, Dalton deduces that John is the Exterminator. Back at the police station, Dalton orders his associate to find a name on the list of suspects who was in the same battalion as Michael. Meanwhile, John tells Maria that Michael has died and when the police storm his apartment, they find it empty. Returning home on the stolen motorcycle, John notices the police. He calls his apartment from a pay phone and instructs Dalton to meet him in the Brooklyn Navy Yard. He threatens to kill Dalton if he is not alone. Unknown to Dalton, the CIA is recording the call. Dalton arrives at the yard and follows John onto a ship. Although John holds Dalton at gunpoint, he fires over his shoulder and tells him that he only wanted the detective to know how victims feel. John surrenders his gun, but as Dalton approaches him, the detective is shot in the chest by a sniper and falls into John’s arms. John tries to help him, but Dalton urges him to escape. When John climbs over the ship’s rail, he is shot by the sniper and plunges into the ocean. Dalton aims at the sniper, but is shot again and killed. As Dalton’s car explodes, the sniper is congratulated by an onlooker who says that “Washington will be pleased.” Some time later, John floats to shore alive wearing a bulletproof vest.