After ramming the SUV and killing Donnelly, Kara injects Reese with a sedative.
Later, Carter is trapped in the wreckage where Donnelly handcuffed her. She wakes up to the sound of a phone ringing and takes the call from Finch. Carter tells him what happened and Finch guides her into finding the key. Once she frees herself, Finch confirms that nobody saw her with Reese and Donnelly and tells her to get out of there before the police arrive. As she leaves, Carter tells Finch that the woman who attacked them was Kara and Finch says that he knows who she is. As he looks at her file, Finch wonders what she wants.
The next morning, Reese wakes up on a moving bus. Kara is seated across from him and greets him, and he admits that he thought she was dead. She points out former agent Mark Snow seated next to him and says that he sent them to kill each other. Reese realizes that Kara has wired him with a bomb vest and she arms it from her cell phone to make sure that he doesn't try to put up a fight. When he asks what she's up to, Kara says that she's brought them all together for one last mission. She gives Reese an earpiece and a list and tells him and Snow that if they complete their assignments then they'll live. Reese discovers she's given him a bag of guns and asks what it's about, and Kara tells him that it's about what they will do now that their careers as spies are dead.
As Carter treats her injuries at home, Fusco calls and asks why she isn't answering her cell phone. He tells her that Donnelly was found dead and the FBI is asking for her because they know she was working a case with the dead man. Carter arrives and Fusco asks if she's heard from Finch and Reese because they sent him to look for her. He notices that she's missing her earring up but before he can follow up, SAIC Moss comes over and talks to her. Carter tells him that the last time she saw him was at Rikers. Moss explains that Donnelly's superiors were worried that he was paranoid and Carter merely says that he was a good agent. Once Moss leaves, Carter checks the wreckage for her earring and Fusco shows her that he already found it. He asks what's going on and Carter says she knows someone who might.
Fusco and Carter meet with Finch, who tells them that there's very little on what Kara was doing when she was killed. Carter confirms that Snow stole a hard drive from the tech company and Finch tells her to fill out a report with everything she learned.
Reese and Snow go to pick something up from a basement apartment. They hear gunfire inside and then a man, Petar, opens the door and invites them in. He's playing a first-person shooter with a friend and Snow asks for the package. Petar gives them a drive but demands another $50,000, and Kara tells Reese to kill him. Reese refuses and Kara remote-arms both bomb vests. Before Petar and his friend can shoot, Kara shoots both of them through the window, tells Reese to get the drive, and warns him that's his last warning.
Corwin and Snow tell Kara and Reese that they're going to Ordos to recover a stolen laptop. Once he's alone with Reese, Snow tells him to kill Kara because she's been compromised. As Snow goes, Kara asks why he isn't joining them and Snow tells her that Reese has been compromised. He tells her to kill Reese and she assures him that she'll take care of it. Later in Ordos, Reese doesn't shoot her when he has the chance, Kara shoots her, and Reese gets out as the American's bomb the company town.
Afterward, Kara wakes up and finds herself surrounded by Chinese soldiers. They take her to a hospital ward. An Englishman, Greer, tells her that she's in the afterlife and says that he already knows almost everything about her. He shows her the laptop that her government was eager to destroy, and Kara along with it. Greer tells her that it's the answer to an interesting question and asks if she wants to know what the question is. When Kara says that she doesn't care, Greer tells her that they'll get along fine.
Kara takes Snow and Reese to a diner. When Reese refuses to eat, Kara says that he's trying to fight back in little ways. Reese tells her that she'll know when he fights back, and Snow smirks. He explains that the two of them killing each other is poetic and they sent the cruise missile to be sure. Two men get up from the counter and leave, and Kara tells Reese and Snow to follow them and steal their car. Reese and Snow knock out the two men and Reese pulls Snow off before he kills his man. They confirm that the two men are ATF agents and Kara tells them that they'll take the agents' place. One man's phone ring and Kara tells Reese to answer it. The man at the other end says that they have a situation and gives them an address, and Kara tells them to take their jackets and throw away their phones.
At the library, Finch assures Bear that they'll get Reese back. Carter calls to tell Finch that the hard drive was from a NSA certified batch made exclusive for military installations. Finch figures Kara is using it to store something. Before he can explain, Finch receives a text message with the letters UXO. Carter confirms that UXO is a military designation for unexploded ordinance. They realize that it's from Reese and Finch sends Carter the location it was sent from.
The ATF and the police are evacuating people after a bomb threat. Reese and Snow arrive and Kara tells them that she called in the threat so the two men can get in. Reese bluffs his way past the security guard on duty and they take the elevator.
Fusco and Carter trace the call to the diner and the ATF agents. They confirm the agents have gone to an office building and Finch discovers that the building has an unlisted floor that belongs to a shell company. He figures that Stanton is after whatever is there.
As Reese blacks out the cameras, Kara gives him the access code to the level 5 DOD facility on the 21st floor. She tells them that they'll face two Delta Force operatives with M-4s. The doors open and Reese and Snow take out the two men and tie them up. One of them hits Snow and he prepares to kill the man, but Reese stops him. Kara warns that there may be signal interference so she arms the bombs on a 15-minute timer.
Greer visits Kara in the hospital as she watches the news broadcasts. He explains that he doesn't work for the Chinese government and tells Kara that the people she worked for betrayed her because they're afraid. The U.S. government has an idea of what will happen next, and Greer's organization thinks Kara can be useful. She chuckles at the idea, but Greer tells her that he can offer her an answer. She only has to tell him the question. Kara asks who did it to her and Greer tells her that the person truly responsible, the person who sold the laptop in the first place, was someone close to her.
Reese and Snow get to the security desk, take out the cameras, and erase the last two hours of backup. Kara directs them to a technician in a temperature-controlled research room.
Carter and Fusco arrive in the lobby and Finch calls from Times Square after hacking the DoD computer. He tells them that the office there is a DoD operation for programmers developing cyber-warfare viruses. Finch realizes that Kara will have Reese and Snow steal a virus and shut down computers nationwide. Carter tells Fusco that they'll have to take the stairs.
Snow and Reese get to a lab and they realize that it's an electronics lab. Kara refuses to tell Reese what they're getting. When a technician, Kevin, comes out, Reese grabs him and herds him back to the lab. They knock out the guard and use Kevin's palm print to open the door. Snow has him log in and download the virus, and Reese realizes that the shielded walls have cut off the signal. He suggests that they do something but Snow says that they don't have time and tells Kevin to take Reese to the servers. Once they move off, Reese tells Kevin that he's going to get him out alive.
Reese calls Finch, who tells him what Kara is stealing. Kevin reluctantly tells him that there are military-grade malware viruses on the servers, which aren't networked to an outside system. Finch determines that Kara is looking for a new virus, Cygnus, powerful enough to shut down The Machine. Reese tells Finch to get clear of the building and then asks Kevin if there's a way to wipe the system. Kevin tells him that it can only be done if there's a security breach to the system.
Reese removes the drive and Snow detects the security breach. He warns Reese that he'll get the both killed and attacks him when Reese refuses. Reese holds him off and their bomb vests activate... and Kara walks in. She says that she knew Reese wouldn't follow orders because he lost his nerve, and Reese tells her that she's too late. Kara tells him that she just wanted them to clear a path for her, tells Kevin to get the drive, and they go to another room. She puts the drive in the computer and explains that she's there to give them something. Kevin explains that they monitor the computer networks from there and Kara can reach any computer from there. She tells Reese that she's doing her job, and Reese tries to get through to her. He points out that they survived and it's not too late to end it. Kara smiles, strokes his cheek, and tells him that she plans to end it. She then resets the bomb vests to five minutes and walks out, sealing the room behind her.
Kevin overloads the room's power supply, causing an emergency shutdown. The emergency battery activates and Reese and Snow destroy it so they can open the door. Outside, they put the ATF jackets on and Reese says that they have to get up to the roof so no one else is killed. Snow clubs him down and says that the CIA has a safehouse two blocks away. Reese warns him that the CIA will consider him compromised but Snow simply wishes him luck and takes the elevator down.
Fusco and Carter arrive and Carter says that she can defuse the bomb. Reese says that she has too much to lose to risk it, and Fusco agrees. When Carter says that he doesn't have to do it, Reese says that he does and she knows it because she'd do the same thing. He thanks them both and Fusco ushers Carter away.
On the roof, Reese finds Finch waiting for him. He gives Finch the drive and tells him to stop whatever is on it, and then draws his gun and tells Finch to stay away. Finch refuses to abandon him and Reese reluctantly lowers the gun. With less than two minutes remaining, Finch realizes that the bomb is triggered by a cell phone. He prepares to hack the phone's unlock code, and confirms that it has five numbers. However, they only get three attempts before the phone locks them out. Finch tries the first number and fails.
On the street, Carter and Fusco look up.
Finch tries the second code and nothing happens.
Kara calls Greer and tells him that it's done. Greer confirms that the computer network is shutting down and Kara demands to know who betrayed her. The Englishman admits that a name is all that he has for her because the person doesn't exist in any known database He gives her the name and Kara writes it down.
As Finch prepares to enter the third code, Reese reminds Finch that he said they'd probably both die. He admits that he'd already be dead if Finch hadn't found him, and tells him to pick a winner. Finch enters the third number... and then hesitates and chooses a different one.
Kara goes to her car and takes her phone out.
Finch enters a different number and the phone unlocks. He then disarms the bomb as both men sigh in relief.
Kara realizes that Snow is in the car behind him. He tells her that she was right and he'd be good at dying. She lunges at him in desperation.
As Fusco and Carter realize Reese's bomb vest didn't detonate, they hear an explosion from down the street. They run to Kara's burning car while up on the roof, Reese realizes what Snow did.
The next morning, Finch is at work when Reese comes in. Bear runs to him and nearly bowls him over.
At the station, Moss comes to see Carter and tells her that they identified the two suicide bombers as Kara and Snow. Moss says that Snow matches the description of the man in the suit and figure the case is closed. He assures her that they'll take of Donnelly and leaves. Fusco comes over and asks if everything is okay, and Carter says that they'll see.
As Reese looks at a photo of Kara, Finch says that all he can determine is that the malware will go live in five months. Reese thanks Finch, who says not to mention it.
The piece of paper that Kara wrote the name down on flutters down from the explosion... with the name "Harold Finch" on it.