Three armed assailants attack a woman who turns out to be NYCPD Detective Sergeant Deke DaSilva of the Street Crimes Unit in disguise. His partner, Detective Sergeant Matthew Fox, immobilizes two of the assailants; Deke chases the third upstairs to a subway-station platform, taunts him and incapacitates him with a scarf. That day in London, terrorist Heymar Reinhardt (alias Wulfgar) bombs a department store. In New York City, DaSilva and Fox serve a high-risk warrant in the Bronx. They raid a drug-distribution spot, where they discover corrupt police officers among the dealers. After the arrests DaSilva meets his estranged wife, Irene, and tells her he loves her; although she initially rebuffs his advances, they eventually reconcile.
Wulfgar meets a member of his network at a party to receive travel documents and money. Suspicious of the delivery man, Wulfgar kills him and three Metropolitan Police Service officers sent to arrest him. He escapes, and the police superintendent berates lead investigator Inspector Hartman. In Paris, Wulfgar meets his partner, Shakka, and learns that his handlers are ostracizing him because the bombing killed a number of children. Wulfgar undergoes facial surgery to alter his appearance and decides to move his terrorist campaign to New York City.
Lt. Munafo transfers DaSilva and Fox to the newly-formed ATAC (Anti-Terrorist Action Command) squad, where they meet Hartman. Hartman and DaSilva clash, since Hartman believes that American police are not ruthless enough to deal with a terrorist such as Wulfgar. Although he hesitates to condone killing Wulfgar, DaSilva absorbs his new training and begins to understand the terrorist. In New York, Wulfgar moves in with a flight attendant and kills her when she discovers his arsenal. Acting on a tip, Munafo orders DaSilva and Fox to search every nightclub the flight attendant had visited. They find Wulfgar in a nightclub and, after a shootout and foot chase through the subway, Wulfgar first takes a woman hostage and uses her as a human shield, preventing DaSilva from shooting. Wulfgar then escapes by slashing Fox’s face with a knife, enraging DaSilva, who vows to kill Wulfgar. At the hospital, Fox admonishes DaSilva for not shooting.
The ATAC squad guards a United Nations function at the Metropolitan Museum of Art. Shakka, infiltrating the party in disguise, corners Hartman on an escalator and kills him. After hijacking a tram car, Wulfgar executes the wife of the French ambassador while DaSilva watches from a hovering police helicopter. Wulfgar demands that DaSilva board the tramway to receive an infant that he wishes to be taken to safety. DaSilva is winched up to the aerial tram and confronts Wulfgar, demanding to know why Wulfgar killed the woman. Wulfgar says that he killed her because he wanted to; considering himself a speaker for people who cannot speak for themselves, he says that all people are victims.
The police agree to Wulfgar’s demands for a bus to escort him and the hostages to an airport, where a jet will be waiting. Wulfgar and Shakka hide among the hostages. As they board the bus, DaSilva plays a hidden recording of a Hartman lecture denouncing Shakka. Shakka, enraged, breaks away from the hostages and Fox shoots her with a sniper rifle. Wulfgar escapes by driving the bus off a ramp into the East River, but after searching the area, the police cannot find him.
At Wulfgar’s safe-house, ATAC finds detailed information on the individual team members and Irene. Wulfgar breaks into Irene’s home, tracking her into the kitchen as she does dishes. As he sneaks up behind to kill her, “Irene” suddenly turns to face Wulfgar, revealing DaSilva in disguise. As DaSilva aims his revolver at Wulfgar, Wulfgar lunges at him; DaSilva fires twice at the terrorist, sending his body crashing into the street. DaSilva walks out of the house and sits beside Wulfgar’s lifeless body on the front steps of Irene’s house.