The film begins with Interpol agent Louis Salinger (Clive Owen) standing outside in the pouring rain in Berlin, Germany. Across the street, his partner Thomas Schumer (Ian Burfield) meets with André Clement (Georges Bigot) in a car. Clement talks to Schumer about how the International Bank of Business & Credit (IBBC) is going to purchase missiles in a deal with China. Both men smoke cigarettes, but Clement remains adamant that the windows stay closed
. Schumer tells him that they can protect him if he turns on the bank. Clement says that he'll think about it and contact him later. Schumer exits the car and Clement drives away. Schumer calls someone and is excited that Clement is going to be their informant, so they can take down the bank. Schumer walks to the road as people walk around him. He signals to Salinger on the opposite side, but then suddenly clutches his arm. Schumer vomits and collapses on the ground. Salinger rushes over through the busy street, but has his head smashed by a side-view mirror of a panel van. Salinger goes down, hearing nothing but a ringing noise, looking directly into Schumer's dead eyes.
Salinger is checked out by a doctor in a hospital, who recommends that he stay overnight so that they can keep an eye on him. Salinger refuses and requests to see Schumer's body. Salinger goes to the morgue and inspects the body. It appears as though Schumer suffered a fatal heart attack, but Salinger doesn't believe it. He thoroughly inspects the body and has the coroner help turn Schumer on his chest. While inspecting his back, Salinger finds a small lesion. He tells the coroner to conduct a full autopsy. Meanwhile, in New York, District Attorney Eleanor Whitman (Naomi Watts) tries to contact Schumer to get an update on how the meet went, but she can't reach him. Salinger calls her office and tells her that Schumer is dead. He also tells her to come to Berlin so that they can meet with police officials. Salinger and Whitman meet the police officials and try to convince them that Schumer was assassinated. The autopsy report found a small trace of prussic acid and cyanide in Schumer's body. For the poison to kill him that quickly it had to have been administered only a minute or so before, Salinger saw the whole thing but didn't notice who the killer was. The police question Salinger about why he and his partner were in Berlin. Whitman explains that Interpol is investigating the IBBC for being the bank of choice for money laundering all over the world, while also participating in other illegal dealings (murder, weapons buying, etc.). Whitman is involved because the New York branch of the IBBC is where they primarily do their shady dealings. Everyone who has tried to testify against the bank has been either murdered or disappeared completely. The police don't see any evidence against the bank, and so they tell Salinger and Whitman to go home. They also inform Salinger that they've read his dossier, and tell him not to make the same mistake he made in Scotland Yard. As they leave, Whitman asks Salinger what the police meant by Salinger's past. He just tells her to read his dossier as well.
Salinger goes back to his home in Lyon and fills a sink full of ice water. As he dunks his head into the sink, he recalls Schumer's death and remembers a man (the assassin) bumping into him after he got out of the car. The next day, Salinger's boss arrives at Interpol headquarters and is surprised to find Salinger there so early. Salinger is determined to bring down the IBBC. He has found a newspaper article about Clement having a freak accident while driving home, the same day Schumer was killed. With Clement dead, they no longer have an informant. Jonas Skarssen (Ulrich Thomsen), the head of the IBBC, gave a statement to the police about Clement. He says that Clement was at his house working on something and then left before he was found dead. Salinger found that Skarssen was lying about the time he said Clement arrived at his house. Salinger wants to talk to Skarssen and try to catch him in his lie (then start to build the case again). Meanwhile, the assassin (Brian F. O'Byrne) meets his handler Wilhelm Wexler (Armin Mueller-Stahl) at a museum. Wexler finds that the assassin is fixated on a particular painting, and asks him why he likes it. The assassin replies that its because he can see the agony on the peoples' faces, and agony is real. Wexler gives him another assignment on a USB key. The assassin hesitates at first, but decides to take the job.
Salinger goes to the IBBC headquarters for his meeting with Skarssen. While waiting, he sees Skarssen walking/talking with a group of men, including Wexler. Salinger shouts out to get Skarssen to talk to him, but is ignored. Salinger is brought into a room and is introduced to Martin White (Patrick Baladi). White is Skarssen's attorney, and he has also brought the bank's attorney to join their meeting. If Salinger wants to talk to Skarssen, he will have to talk to White first. Salinger is pissed that he's being jerked around, but stays for the meeting. He questions White about the time Clement arrived at Skarssen's house, and White gives the wrong time. Salinger calls him on lying and tells him that the police report he has states a different time. The bank's attorney inspects the report, and then pulls out another report. He says that the report Salinger has was a preliminary draft, and so has errors. The official report, which is in his hand, says that the time White gave is correct. Defeated, Salinger leaves the headquarters and calls Whitman on the phone. He says that they changed the report and there's nothing he can do. While talking, someone bumps into Salinger and walks towards the bank. Salinger freaks out, thinking that hes been poisoned as well, and confronts the person who bumped into him. It turns out to be an innocent woman, who thinks that Salinger is crazy.
Salinger visits his boss at home and tries to get him to come outside. His boss refuses, and so Salinger makes his way into the house. He smashes his boss's phone to pieces and pulls out a hidden wiretap from it. They go outside, and Salinger says that he also found a wiretap in his phone. The bank bugged them, which is why they wrote up a new report before Salinger went to visit. Meanwhile, Whitman calls Clements's widow and tries to question her about her husband, but she hangs up. She leaves a message for her, giving her cell phone number and telling her to talk. The widow picks up the phone and says that she doesn't know anything about why her husband was killed. She hangs up again, but then text messages Whitman's cell phone. They reply back and forth, and the widow tells Whitman to talk to Umberto Calvini (Luca Barbareschi). Also, during this time, we see the assassin practice firing at a target a certain distance away. He then carefully loads the bullet shell into a container to save for later. Salinger looks into Calvini and finds that he is the head of a weapon s industry corporation. He also is running for Prime Minister in Italy. Salinger and Whitman travel to Milan to question him about Clement and the IBBC. Meanwhile, we see a couple of exchanges, ending with a package being handed over to a uniformed senior cop. Salinger and Whitman show up at a political rally, where Calvini will give a speech. They enter a nearby building to meet Calvini. While waiting, Whitman says that she read Salinger's dossier and found out what happened to make him quit Scotland Yard and join Interpol. He had found a good informant in the IBBC to help him bring them down, but the IBBC got to his informant and made it appear as though he was unreliable. They then caused the informant and his family to die in a car accident. Everyone wrote Salinger off and they buried the case. They meet Calvini, and he candidly explains that the IBBC has purchased a bunch of missiles from China to sell to another country. They then came to him to buy guidance systems because he's only one of two people in the world who can supply them. However, Calvini refused to do business with them and turned them down. Clement was his friend in the IBBC. Calvini warns Salinger and Whitman that the IBBC control everything and everyone. They supply countries with weapons to control the wars, which makes them control the debt in war zones. He promises to talk more with them after the rally is over.
Calvini goes outside and attends the rally. Salinger, Whitman, and an Italian detective decide to get some drinks at a bar next door while they wait. In a nearby hotel, we see a hitman setting up a rifle and aiming for the stage. Calvini starts to give his speech, and the hitman sets off a countdown for sixty seconds. When the minute is over, he tries to shoot Calvini's head but misses due to a sudden movement. Immediately after, a second shot is fired and Calvini is shot in the head. The hitman is confused, since he didn't fire the second shot. The crowd panics and everyone runs off. The uniformed cop from earlier blasts his way into the hitman's hotel room and pumps him full of bullets. After his colleagues leave, the cop shoots the hitman in the head to finish him off. He then plants the shell that the assassin fired earlier on the floor. Salinger runs to the hotel while Whitman and the cop follow. While everyone flees, Salinger spots the assassin. He follows after him through an alley, but loses him once they get to the backstreet. Whitman and the detective also get to the street. Whitman sees the assassin in a car and slowly approaches. The assassin starts up the car, crashes into Whitman, and speeds off. Salinger and the detective are shocked and rush over to her. She appears to be fine, and the detective gives Salinger his gun, telling him to pursue the assassin. Salinger runs on foot and eventually comes to a crowded intersection. He spots the broken windshield of the car and approaches it, but finds that the assassin has escaped.
Whitman is checked out at the hospital and is fine apart from some bruises. Salinger and Whitman go back to the rally site, which has been sealed off by police. They are let through and begin to inspect the stage. They notice that the trajectories of the two bullets fired are different from one another. They go onto the roof of the hotel where the hitman was killed and Salinger realizes what happened. The assassin was on the roof, with the hitman a couple of stories below. They both set off a countdown for sixty seconds once Calvini started to talk. When the hitman missed, the assassin fired and got the head shot. The second bullet shell in the hotel room was placed to look like the hitman was alone and fired both shots. And since the hitman was connected to the Red Brigade, Calvini's death looks like a political assassination. As Salinger visualizes how the assassin got away, he comes across a puddle on the roof. He has the cops drain the water and then they find the footprint of the assassin in it. Salinger recognizes the footprint from a murder years ago, and realizes that the IBBC keeps on using the same assassin. Also, due to the footprint, they determine that he uses a leg brace to walk. If they can get to the assassin and turn him, they can bring down the bank. The corrupt cop shows up and informs them that their superiors have ordered them back home. Their investigation is hereby closed. Salinger and Whitman go to the airport and can't believe they're being shafted like this. As they say goodbye to their cop friend, Whitman notices the metal detector nearby. If the assassin left through the airport, he would've had to show his leg brace once he stepped through the metal detector. They review the security footage and find that sure enough the assassin was there earlier, but since he was aware of the camera he had his head turned away (so they dont have a clear image of his face). They find that he went on an airplane to New York, and so they head on the next flight to NYC.
Once Salinger and Whitman arrive, they are greeted by NYPD detectives, Iggy Ornelas (Felix Solis) and Bernie Ward (Jack McGee). The detectives managed to get a clear screenshot of the assassin's face when he landed in New York. And since he has a leg brace, he must have been a particular doctor's patient to get the shoes that he's wearing. Meanwhile, we see the assassin running on a treadmill at a gym. Salinger, Ornelas, and Ward locate Dr. Isaacson (Tibor Feldman). They go to his apartment and knock on the door. He answers, but then shuts the door, saying that he hasnt done anything and seems nervous at letting them into his apartment. Salinger scares Isaacson into cooperating with them by saying that the assassin kills doctors. Elsewhere, Skarssen is at home playing the Asian strategy game Go with his son when he gets a video conference call from White, Wexler, and his senior staff. It's revealed that they had Calvini killed so that they could deal with his son's for the guidance equipment for the weapons. They also know that Salinger and Whitman are close to finding their assassin. It is decided that they won't allow anything to mess up their deal with the Calvinis.
Salinger and the detectives look through all of Isaacson's patient files for those who have the specific leg braces. One file has a dead phone number listed and no photo of the patient. Also in the file is an address, which was where he would get dropped off by a taxi every time he left the office. Whitman's boss chastises her for wasting time on the IBBC case and tells her they have 1 more chance. Salinger, Ornelas, and Ward go to the address but find that its an empty lot. Still, they figure that the assassin must live around there. Ornelas goes to get some coffee and as he pays, he spots the assassin walking down the street. Ornelas runs out of the store and gets Salinger and Ward. They follow him through the streets until he stops at a payphone. He calls someone, and tells him to meet at the Guggenheim Museum. Salinger and the detectives follow the assassin to the Guggenheim and blend in with the crowd. Wexler shows up and Salinger recognizes him from before. Wexler tells the assassin that Salinger is his next target, since he's getting too close to them. Wexler leaves and Ornelas follows him. The assassin gets ready to leave when he sees a reflection of Salinger and Ward spying on him. Salinger realizes that they're blown and so they confront the assassin. They hold him at gunpoint and prepare to arrest him, but the assassin says that the bank will never let them bring him in. The assassin is suddenly shot in the chest and falls over. A gunman shoots Ward in the throat, causing him to fall onto Salinger. Ward bleeds all over Salinger and painfully dies. The gunman is about to kill Salinger when the assassin shoots him through the forehead. It turns out that a whole hit team is in the museum, and a massive shootout ensues. Salinger grabs Ward's gun and kills some henchmen. The assassin also saves Salinger from being killed again. The assassin was wearing a bulletproof vest, and so he's unharmed from being shot before. He tells Salinger that they need to get out the museum, since the hit team is meant for both of them.
During the shootout, Salinger is wounded in the side of his face. He and the assassin realize that the only way out of the museum is the spiral ramp, which is scattered with hitmen. They try to shoot their way out floor-by-floor, but keep on getting held down. Salinger shoots a hitman and tries to grab his gun, but the hitman fights him over it. Salinger shoves his finger into the hitman's bullet wound and causes him to unload his machine gun into the roof, showering the museum with glass. Salinger manages to shove the hitman over the balcony, where he falls to his death. The assassin is shot in the hand, and then four times in the stomach. Salinger smacks him around to make sure he doesn't die, and then shoots out a giant ceiling piece, causing it to crush some gunmen below. Salinger and the assassin manage to elude the last two gunmen and escape from the museum shortly before the police arrive. Salinger carries the assassin to a nearby park, and the assassin says that he was right all along they would never allow him to be taken into custody. The assassin dies, and Salinger is found by the police.
Whitman visits Salinger at the police station, where a detective tells them that the cops were told to detain both of them. Whitman and Salinger manage to escape from the police station and drive off. Whitman shows Salinger a file and drives him to a building, where Ornelas is waiting for them. He caught up with Wexler and is keeping him downstairs. He tells Salinger to turn Wexler so that Ward didn't die for nothing. Salinger goes downstairs and meets Wexler. He knows that he was the assassin's handler and knows that he set him up to die. Wexler says that the reason why Salinger failed to bring down the IBBC and will continue to fail is because the IBBC controls everyone. All government agencies and criminals invest in the bank so that they can do things outside the law. Wexler was a former East German communist secret police and Salinger is puzzled how he came to be so dedicated to a western bank. Wexler wearily hints at selling out his beliefs and is not happy anymore. To bring down the bank, Wexler tells Salinger he will have to also go outside the law. Salinger tells Whitman to walk away from the case and write him off. She wants to see the case through to the end, but Salinger says that the bank will go after her family. Its better if he goes at it by himself. Whitman eventually agrees and says goodbye.
The IBBC lawyer White and others go to the Calvini organization to sign the contract for the guidance equipment. However, the Calvini security team suddenly shows up and orders White and his guys to leave immediately. It turns out that Salinger informed the Calvini sons that the IBBC assassinated their father. While driving away, White is informed that the Calvinis know about the assassination. Whites car enters a tunnel, but doesn't come out. Later on, while watching a news segment on a general staging a coup de tat (which the IBBC supported), Skarssen sees a report about White's death. He realizes that the Calvinis are sending them a message, but reassures his colleagues that everything will move ahead. So instead of buying the guidance equipment from Calvini, they will have to buy it from Ahment Sunay (Haluk Bilginer) in Turkey. Currently, Sunay is in Istanbul for his cousin's funeral. Skarssen plans to travel there to negotiate a deal. Wexler calls Salinger and tells him that the meet is in Istanbul.
In Istanbul, Skarssen and Wexler arrive at the funeral. While waiting for Sunay, Wexler excuses himself to use the bathroom. Salinger is waiting in the bathroom with an earpiece. Wexler planted a bug on Skarssens jacket, so when they meet Sunay Salinger will be able to record their conversation. Sunay greets Wexler and Skarssen while Salinger watches from afar. Sunay has Wexler wait outside while he takes Skarssen into a building to talk business. Salinger sneaks into the building because he has to be within a certain level of distance to hear the conversation. However, he's soon discovered by guards and thrown out. Meanwhile, a man approaches Wexler. He looks up and knows what's going to happen next. After negotiating, Skarssen goes outside and finds Wexler slumped against a pillar. He tells him to wake up, but then notices a hole in his jacket. Skarssen opens his jacket to find that Wexler has been shot and killed. He then panics upon seeing Salinger, who starts to approach him. Salinger grabs Wexler's gun and stalks Skarssen through busy markets. Skarssen tries to shake him, but Salinger continues to follow him. Scared, he runs onto a rooftop and flees. A part in the roof is destroyed, and so he can't run any further. Salinger, gun in hand, introduces himself. Skarssen says that he doesn't have the authority to arrest him. Salinger says who said anything about arresting you? and aims the gun at him. Skarssen says that if he kills him, it will solve nothing. Someone else will take his place, and the IBBC and 150 other banks will continue to thrive. If Salinger were to kill him, it would only quench his blood thirst. As Salinger contemplates killing Skarssen, a shot is fired. Skarssen is shot in the chest and collapses on the roof. A gun is then held to the back of Salingers head. The shooter is the same man who killed Wexler. He takes Salinger's gun away, and then walks down to where Skarssen is barely alive. He shoots Skarssen again, this time in the head to finish him off, "with greetings from Mario and Enzo Calvini". The film ends with the hitman walking away, telling Salinger "Grazie" (Italian for thank you). We hear a ringing noise and the screen cuts to black.
During the end credits, we see newspaper headlines about Skarssen's death. He was replaced by one of his colleagues, who continued the illegal activities of the IBBC while making it appear as though they are a clean bank. The last newspaper clipping says that Whitman, in a promoted position in Washington, is going to perform another investigation into the IBBC.