Paul Kersey (Charles Bronson) returns to New York City, having assumed the name Paul Stewart under the witness protection program. He is invited by girlfriend Olivia Regent (Lesley-Anne Down) to a fashion show. Backstage, mobster Tommy OâShea (Michael Parks) and his goons muscle in. Tommy threatens Olivia, who is his ex-wife and mother to their daughter Chelsea (Erica Lancaster). Olivia later informs Paul of her ex-husband's behavior after he finds bruises on her hand. Paul confronts him, but Tommy points a gun at Paul. The confrontation ends with the arrival of Chelsea.
D.A. Brian Hoyle (Saul Rubinek) and his associate Lt. Hector Vasquez (Miguel Sandoval) visit Paul's home. He informs them about Tommy OâShea. Hoyle says they have been trying to nab Tommy for years, and he wants Olivia to testify.
That night at a restaurant, Paul proposes to Olivia, who accepts. Olivia excuses herself to the bathroom and is attacked by Tommyâs associate, Freddie "Flakes" Garrity (Robert Joy), who bashes her head on a mirror, disfiguring her face. Freddie escapes, although Paul gets a look at him. At the hospital, where Paul is told Olivia will need reconstructive surgery, he talks with Lt. Mickey King (Kenneth Welsh), who has been working on the OâShea case for 16 years. King warns Paul not to pick up his old habits and to let the police handle it.
Tommy kills several people including a female police officer. Paul and Olivia are attacked by Freddie and his friends, who shoot Olivia in the back, killing her as the couple tries to escape. Paul jumps from the roof of his apartment, where he lands in a dumpster, and is retrieved by the police. Tommy is cleared of involvement in Oliviaâs death and seeks custody of their daughter. Paul assaults Tommy, who leaves him unconscious. He decides to return to his vigilante ways and is assisted by Hoyle, who learns his department has been corrupted by Tommy. Paul poisons one of Tommy's men, Chuck, with a cannoli. He then kills Freddie by blowing him up with a remote-controlled soccer ball. Tommy finds out from an informant that Paul is the vigilante and will be going after him for killing Olivia. The informant, Hector Vasquez of the NYPD, tries to kill Paul himself, but Paul gets the upper hand and kills him. Fellow officer Hoyle arrives and finds out Tommy wants both him and Kersey dead. Hoyle tells Kersey he must never see him again, and Paul agrees.
Tommy hires three thugs to take care of Paul, using Chelsea as bait. Paul rescues her. Lt. King is wounded by Tommy. Paul kills one of Tommy's men by shooting him into a large wood chipper. He picks up an empty beer bottle, smashes it, and cuts Tommy's face in retaliation for what he did to Olivia. Armed with a shotgun, Paul corners Tommy and knocks him into a pool of acid, where he disintegrates. King thanks Paul for saving his life. Paul goes to rejoin Chelsea, calling out to the injured King, "Hey Lieutenant, if you need any help, give me a call".
Tommy dies after being knocked into a pool of what?
Acid