In Washington, D.C. at a train station, a man approaches another man on a bench, shows him a gun, and prepares to mug him. The man on the bench notes that he's not well dressed and points out the mugger isn't going to get any money. When the mugger demands his victim's watch, the "victim" quickly removes the clip from the muggers' gun and tells him to leave. As the mugger runs off, a bleeding Chance sits down next to the victim, who warns that Chance will have a hard time killing him with so many witnesses. Further, if he opens fire, innocents will be hurt, and Chance will be haunted by the deaths. Chance tells the man, Baptiste, that the train will arrive in 4 minutes and everyone will be gone. Baptiste wonders if Chance can still try and kill him, and Chance says that they'll find out.
8 Hours Earlier
Winston and Chance pose as detectives and arrive at a murder scene. The detective explains that the victim's fingerprints were burned off and all forms of ID removed. Winston explains that the murderer is an assassin for hire. When Chance notices the victim's watch is missing, Chance says that it's Baptiste. Winston warns that Baptiste has a six-hour head start and admits that he knows that Chance wants revenge… and he won't stand in the way.
Emma Barnes answers a knock at her door and finds Chance there. She shoves him to the ground and prepares to arrest him, explaining she was humiliated and suspended after Chance vanished. A man, Roger, comes in and Emma tells him to get her handcuffs. Chance explains that he needs her help as Roger gives Emma the handcuffs and leaves. As she prepares to call in the arrest, Chance says that he needs her help with Baptiste and it can make her career. Emma reluctantly hears him out as Chance explains that Baptiste killed the John Doe's identity because the victim worked at the UN. Now Baptiste has the dead man's access papers and plans to target a major international figure. Chance warns that Baptiste won't fail unless they stop him, and Emma wonders why Chance is the only one who knows about Baptiste. Chance admits that he's the one who trained Baptiste.
Baptiste wonders why Chance broke up their team and doesn't see why he places value on life, and is amused that now Chance is trying to save people. He points out that the people that Chance couldn't save were the people he cared about most.
Emma wonders if Chance is an assassin but he insists that it's not important at the moment. Winston and Guerrero arrive with their new team member: Layla, whose company they ruined. Layla and Guerrero start setting up in Emma's apartment while Winston warns Chance that Emma is better off staying objective around Chance. They notice that Emma has a wall dedicated to tracking down Chance. Chance suggests they break into Deputy Director Lynch's office to get the white list of visiting dignitaries and their itineraries. He insists that it's important enough to risk his freedom and that Baptiste will use his stolen credentials to get into the UN.
Baptiste meets with Lecavalier, the security chief for the UN, and tells him that he's discovered a security breech and an assassin is on the loose. Lecavalier calls Lynch and notifies him of the breach and that they'll be coming. When Lecavalier insists on going, Baptiste kills him and takes his watch.
Chance and Emma go to FBI Headquarters and use Emma's credentials to get in. They leave behind a case with electrical equipment that lets Layla tap into the mainframe. Layla hacks the FBI security systems while Guerrero eats Emma's food. Guerrero explains that they're freelancers while Layla realizes that the FBI computer techs have detected her intrusion. Their efforts will slow her down.
Emma and Chance get into the elevator, but she hesitates and notes that pushing the button will commit herself. Chance hits the button and then asks about her date, Roger. Emma insists that it's none of his business, and Chance notes that she was wearing a third-date bra. They arrive on Doyle's floor while Emma insists that it was a first date.
Baptiste arrives at FBI headquarters and uses his credentials to go up and see Lynch.
Baptiste notes that Chance left because of a girl, Katherine Walters, not a principle. He admits that he took no pleasure in killing her, and was embarrassed because he had to clean up Chance's mess. Baptiste wonders how Chance could throw away everything for a woman he barely knew, and points out that he's doing the same thing now. This time, Baptiste says that what happened to Emma is Chance's fault because he brought her into it.
Emma worries that what they're doing is a bad thing. They get to the door but discover that Layla hasn't hacked the security permissions yet. While they wait, Chance tries to convince Emma that he's a good guy and wants a chance to prove it over dinner. She turns him down. Layla hacks the systems and they get in. The room is filled with FBI agents on detail, and Emma bluffs her way in. She identifies Chance as a UN liaison, and Agent Folster checks his files. Guerrero and Layla quickly insert Chance fake credentials in, racing against time. Meanwhile, Chance and Emma look around and realize that China and Taiwan are having secret meetings and the FBI detail is in charge of protecting it. Chance's fake ID is okayed and he's allowed in. Meanwhile, Guerrero and Winston start putting out feelers to find out where the meeting is happening.
Emma warns Chance that Lynch is the only one who will know where the meeting is being held. Chance spots Baptiste talking with Lynch, but Emma warns him not to open fire. Baptiste spots Chance and ducks out. Emma reluctantly goes with Chance after Baptiste, who has fled the building. Chance figures that Baptiste learned the location of the meeting from Lynch. As they drive after him, Baptiste calls Emma and asks if they're an item. Chance takes the call and suggests they get together. Baptiste agrees and then rams their car.
Baptiste explains that their old boss trained them both, but Chance abandoned them and took his teacher's name. The assassin had to keep their old boss in check despite his anger, but now he's going to have to explain why Chance is taking it personal and wonders if he's losing his edge.
Baptiste takes out a silenced gun and moves in. Chance grabs the unconscious Emma's gun but can't get out of the jammed car door. He holds Baptiste off long enough to get the door open and wake up Emma. Baptiste shoots the leaking gas and walks away, and Chance gets Emma out just in time to avoid the explosion.
As the police approach, Chance updates Winston and Guerrero. Winston leaves to help them while Guerrero has Layla tap into the phone company records to track down disposable cell phones and locate the one that Baptiste used to call Emma. Once she succeeds, Guerrero calls Baptiste and talks about the man who tried to hire him to steal files on Chance, the man he killed. Baptiste claims he doesn't know who the man worked for, and Guerrero then asks for 10% of the take in return for stopping Chance. Baptiste doesn't believe him and asks how old Guerrero's child is. When Guerrero says nothing, Baptiste says that by the time he's finished, Guerrero will beg to return. Guerrero hangs up and tells Layla that Baptiste did give something away.
Emma and Chance take refuge in an alleyway, and she demands to know who Katherine is. Chance explains that he used to work for some bad people, and his old boss found Chance when he was young and angry, and manipulated him into killing people. Katherine Walters was his last assignment, and he couldn't kill her. Emma realizes that Chance loved her, and he explains that he tried to protect Katherine but they sent Baptiste and he succeeded where chance failed. Winston arrives and picks them up, and explains that Guerrero heard church bills over the phone as he talked to Baptiste. There's only one location that fits, in Georgetown, and they figure the campus is the perfect place for a secret meeting.
An electric manager approaches Baptiste, who is disguised as a worker working on a manhole cover. Baptiste shoots the inspector and looks at his wrist watch, and then dismisses it as poor quality.
Baptiste figures he'll learn if Chance has become a new man, or if he's still the killer that Baptiste once knew. Chance points out he would have killed Baptiste for what he did, and notes that if he kills him, there'll be no consequences. Baptiste warns that the old man will come after Chance and everyone he's ever cared about. The train arrives and the passengers begin to board.
Chance, Winston, and Emma arrive at Georgetown and spot where Baptiste has entered the steam tunnels. They go in after him but Emma goes to alert the security details. They realize that to be thorough, Baptiste will blow up the entire building. They find the bomb that he's planted, designed to be activated by remote. While Emma goes to notify the FBI and get an evacuation organized, Chance goes to find the best position for a sniper.
Emma tries to warn the FBI but Lynch demands answers. Meanwhile, Baptiste knocks out a sniper and prepares to open fire. He watches as Lynch has the FBI agents arrest Lynch, but Folster arrives and confirms her story. Realizing the evacuation is going ahead, Baptiste prepares to trigger the bomb. Chance arrives and shoots the cell phone out of his hand. The two men battle while below, Emma realizes that one person is unaccounted for and goes inside after them.
Baptiste stabs Chance in the leg and picks up the cell phone. He triggers the bomb and they watch as it explodes. Chance manages to remove the knife and throw it at Baptiste, hitting him in the chest and knocking him over the edge of the building. Winston arrives and tells Chance that Emma was in the building when it blew up. Chance goes to check on Baptiste and discovers that he's gone. Winston confirms that Layla hacked the cell phone records and confirmed that Baptiste is escaping via Amtrak. Winston calls Guerrero and has him locate the nearest stations.
Baptiste tells Chance that he can run despite his injuries, but he's not going to leave. He figures Chance wants him to run so he'll have an excuse. Baptiste refuses to make things easy for Chance. They both stand up and Chance draws his gun. Before Chance has to shoot, Emma arrives. She explains that she made it out the back, and everyone survived. Emma says that it's over, but Chance prepares to shoot Baptiste. She tells Chance to put the gun down, saying it's not him anymore. Chance considers… and then put the gun down. As Emma takes Baptiste away, he tells Chance that he's lost his edge. FBI agents take Baptiste away, and Chance admits he's relieved that Emma is okay. She thanks him and goes off to close the case, letting Chance get away. Emma turns to accept his dinner invitation, but discovers that he's vanished.
Layla is packing away the gear and cleaning up Emma's apartment. She asks Guerrero if it's always like that, but admits that she enjoyed saving people and capturing an assassin. Guerrero warns her that she'll crash later after the adrenalin wears off, and nothing is ever over.
As Baptiste is lead away, he admires an FBI agent's watch and smiles.