A bomb explodes in the plaza of the Colombian Consulate building in Los Angeles, tragically taking the lives of nine individuals, which includes a group of Colombian officials and American intelligence agents. Among the victims are the wife and son of LAFD firefighter Gordy Brewer (Arnold Schwarzenegger), who, arriving to pick up his family, is injured in the blast. In the aftermath, a tape is sent to the U.S. State Department featuring a masked man identifying himself as "El Lobo" (The Wolf), who claims responsibility for the attack as retaliation against the oppression faced by Colombia from America.
The FBI suspects the perpetrator is a Colombian terrorist known as Claudio Perrini (portrayed by Cliff Curtis). Following the incident, CIA Special Agent Peter Brandt (played by Elias Koteas), the Chief in Colombia, faces severe consequences from a Senate Oversight Committee, leading to the halt of CIA operations in the country. Frustrated by the bureaucracy surrounding the investigation, Gordy ventures to Mompós in pursuit of Claudio but is arrested for his illegal entry. A guerrilla cell orchestrates a prison break to free their compatriots and attempts to capture Brewer for ransom. Though Brandt's team is informed about Brewer’s situation, they arrive too late to thwart the escape.
Once free from imprisonment, Brewer navigates through guerrilla territories, acquiring a pass from Canadian mechanic Sean Armstrong (John Turturro), who provides insights to connect him with drug lord Felix Ramirez (John Leguizamo), the man behind the cocaine operation funding the guerrillas. Posing as a mechanic sent to repair a generator, Brewer plants improvised explosives that obliterate the drug facility. In a grim twist, Felix is executed for the destruction, witnessed by a concealed Gordy.
Brewer manages to infiltrate Claudio’s compound, laying plans to eliminate him, but is captured when he uses himself as a shield for a woman, later revealed to be Selena (Francesca Neri), Claudio’s wife. Selena, having experienced her own tragic loss in a bombing, sympathizes with Brewer's quest for vengeance, revealing Claudio's intentions for another attack in Washington, D.C.
As Brandt's unit tracks Claudio's location, they launch a tactical assault. During the ensuing chaos, Selena helps Brewer escape, and they both make their way back to the State Department in Washington, D.C. Under pressure, Selena discloses that Union Station is the target of the imminent attack. She slips away under the pretense of needing the restroom, disregarding her adopted son Mauro. Brewer notices her mimicking the gesture made by El Lobo in the initial tape and realizes the shocking truth: she is El Lobo.
Thinking quickly, Brewer deduces that the actual target is not just Union Station but the State Department itself. With urgency, he throws Mauro’s toy dinosaur—rigged with a bomb—out the window moments before detonation. In a tragic turn, Brandt finds himself fatally shot in an elevator while trying to confront Selena.
The pursuit leads Brewer into the building's basement where Selena and Claudio attempt their escape on a motorcycle through the tunnels. Brewer manages to shut the gates to block their exit and, in a desperate act, ruptures gas lines, igniting an explosion during their attempted getaway. Though they survive the blast, a physical confrontation ensues between Brewer and the couple. Selena meets her end when she is electrocuted by exposed circuitry, while Claudio suffers a fatal injury as Brewer hurls an ax into his chest. Escaping the chaotic scene, Brewer carries Mauro to safety.
In the aftermath, a newscast voiceover announces that Brewer will be awarded the Presidential Medal of Freedom for thwarting what could have been one of the deadliest terrorist attacks in U.S. history.
