The Machine monitors a conversation in Serbia between a man and a woman. The woman, Sanja, confirms that the girl saw everything. The man, Charles Harris, says he can keep the girl safe.
In New York, Reese and Finch go to a hotel and Finch talks about hotels at lengths. They go in via the employee entrance and change into their employee clothing. Their new Number is Mira Dobrica, a maid who spends most of her time at the hotel. She came to America in 1999 and her computer record is spotty, and Finch has contacted Immigration. Finch has gotten Reese in as a bellhop while he works as a concierge, and warns Reese that there are 700 guests in the hotel and they have no idea who.
The manager, Derek Fowler, comes over and thanks Finch for coming in on short notice. He introduces Bud Garrison, the doorman, and explains that they're hosting an event for the Association of Aviation Technology the next time. Derek then orders Reese to work. Once Finch is at the desk, he sends Reese to check on Mira. He gets in an elevator and finds Zoe taking the car up. They chat briefly and Zoe admits that she's working a job. Once she leaves, Reese plants a camera on Mira's cart and then hears her in a guest's room, insisting she didn't steal his money. The guest is Tug Brantley, a CEO for an energy drink company. Tug tries to blackmail her into having sex with him but she walks out. Reese comes in and stops him, warning that he'll go to the police if he persists with the sexual harassment.
Tug backs down and Reese checks with Mira. She says that she could handle it but thanks him for his intervention. Mira warns him that Derek has understaffed bellhops and the other one is lazy. As Mira goes back to work, Reese clones her phone and tells Finch that he likes her. Finch has heard back from Immigration and learned that Mira is a survivor of the Kosovo War and sought refugee status. Mira was 16 at the time and her family didn't make it out.
As Finch continues working, he hacks into all of the hotel's cameras. He spots Derek and Bud meeting with Mira. Derek tells Mira that the police was asking questions of their side operation but he figures that Mira wasn't the one who gave them away.
The Special Council calls Hersh once he gets out of Rikers, and Hersh assures his boss that he knows who he is looking for. Their source has become compromised since Reese went into the DoD facility, and Hersh figures that he can follow any messes to Reese and then dispose of him. Hersh breaks into a police car, turns on the scanner, and drives away.
At the station, Cal comes in to see Carter and admits that he did something wrong. He explains that his mother set him up with a woman but he told her that he's seeing someone else and it could be serious. Cal asks if Carter has told her son anything, and Carter admits that she's told Taylor a few things and asks if Cal will meet him. He agrees to meet Taylor but then sees SAIC Moss come in and tells Cal she'll talk with him later. When Carter talks to Moss, he explains that he saw a recommendation in Donnelly's file about his offer to make her a FBI agent. Carter says that she's still interested in and Moss says that he'll begin the procedure. He warns her that she will need to take a polygraph test and promises to set it up that night. Once he leaves, Fusco, who has overheard the conversation, asks his partner if she's going to go through with it and she says that she is.
At the hotel, Reese checks in with Finch and admits that he still hasn't spotted the threat to Mira. He spots a woman with a different guy then she was with earlier and suspects that Derek's side business is prostitution. Finch has Carter checking on solicitation activity. Derek comes over, sees Reese lurking around, and tells him to get back to work. Once Reese leaves, Carter calls in and tells Finch that Vice picked up a girl on an anonymous tip, but the prostitute didn't say anything and Bud posted the bail. She then asks Finch about the FBI offer and he figures that she's concerned about the polygraph. Finch explains that polygraphs detect physiological response and suggests that she try and lie on one of the baseline questions, and stay clear of them for the time being. Finch then calls Reese and tells him that Carter has confirmed that Derek is running an escort service.
Mira is on her rounds when Harris comes out of Room 3215 and says that they need to talk. Finch checks Harris' room service bill and discovers that he drinks a lot more than he eats. Reese is busy with a guest, Betty, who invites him to stop by anytime. Reese quickly leaves and goes up to Harris' room. He listens at the door and hears Harris telling Mira that she needs to listen to reason. Reese barges in and Harris quickly picks up some photos. Mira wonders why Reese is there and he claims he came in to check the mini-bar. Harris calls Mira "Miss Brozi" and asks her to reconsider. Outside, Mira complains that Reese keeps walking in on her and figures that he's working with Derek. When Reese says that he knows about Derek's escort service and figures that she tipped off the police, Mira says that he should stay out of it and she doesn't need help from someone like him.
Reese checks back with Finch, who has confirmed that Harris is a freelance journalist who is persona non grata in a half-dozen countries because he's objected to their rulers. They figure that Mira may be one of his contacts, and Reese points out that a man in a turtleneck has been in the lobby watching the desk since they arrived. They make a call and Zoe comes in and sits down with the man. She starts talking with him and then spills her drink on him. The man gets up and talks to someone on an earpiece. Finch checks the surveillance cameras and discovers that other men are moving in to cover the absent spotter. Reese identifies it as military recon tactics and they wonder who would send in a hit squad to kill a maid.
The spotter heads back downstairs after cleaning up and Reese checks on his room, which his registered to Peter Krief. They figure it's a forged ID Reese searches the man's luggage, while Finch hacks Harris' computer via the hotel wi-fi. Reese finds files on Harris and articles he wrote about Rudko Petrovic, a colonel in Serbia who allegedly committed war crimes in Kosovo and is running for prime minister. Finch checks Harris' notes and discovers that Mira witnessed Petrovic ordering the execution of her family. They realize that the hit squad will move on Mira as soon as they confirm she's Harris' source.
Finch calls Fusco in and sends him a photo of one of the hit men. The team returns to its original positions and Reese has Finch watch them while he approaches Mira. She brushes past him and goes toward the side exit, and one of the killers moves in. Reese takes him out and hides the unconscious man, and tells Mira that he knows why they're after her.
Gunshots are heard from Harris' room and Finch loses the connection to the reporter's computer. The security cameras go out and Finch sends Reese to Harris' room. After Reese finishes tying up the killer, he takes Mira with him to check on the reporter.
At the station, Moss begins with some baseline questions for Carter. She says that she smoked marijuana in college and Moss admits that she's the first one who ever admitted it.
Finch tells Reese that Harris checked out by remote. Reese bursts into Harris' room and confirms that he's not there. Mira notices that a chair has been moved and when Reese pushed it away from the wall, they find bloodstains. He figures that the hit squad moved fast and cleaned things up as best they could. Mira tells Reese that she thought Harris was a drunk. She escaped with the help of a neighbor, Sanja, and Harris found Sanja and recorded her saying that Mira could identify the colonel. Sanja turned up dead two weeks ago and Harris told Mira that she had to go public to ensure her safety. She refused and now Harris is dead. Reese promises to get her out but has to know how the hit squad determined she was the witness. Mira says that she didn't tell anyone and Reese uses his cell phone to dial hers. There's static on the line, indicating a strong electromagnetic field nearby. Reese finds a bug hidden in the air vent and realizes that they're next door.
Reese breaks into the next room and takes out the female member of the hit squad. Mira runs for it and gets into the elevator. The doors close just as Reese gets there, and Finch taps into the camera just as the passenger with her blocks out the camera. He draws a gun on her and tells her to use her key card to take the car to the basement. Finch stalls the car and Reese grabs a fire axe. Fusco and Finch call to warn Reese that the two spotters in the lobby are leaving their positions. One of them takes a large trunk out and Finch, realizing that it contains Harris' body, tells Fusco to keep them in the hotel.
The killer in the elevator demands the recording Harris made of Sanja. Meanwhile, Reese slides down the cable and opens the hatch, opening fire. The killer takes Mira as a shield but she shoves away and Reese shoots the man in the shoulder, and then drops down and knocks him out. Meanwhile, Fusco walks to the back exit, bumping into a man who says he's looking for the bathroom. The detective gives him directions and moves on.
Reese is ready to go but Mira says that Harris gave her the disk with Sanja's recording. She has it in her locker and Reese says that he'll go back for it once he gets her to safety. When Reese addresses the camera, Mira wonders who he's talking to and Finch calls to introduce himself as a friend.
Fusco catches up to the hit squad outside as they load the trunk into their van. Fusco takes the two men out and confirms that Harris' corpse is in the trunk. Reese calls to tell Fusco to meet him and he says that he'll be there as soon as he calls it in.
Hersh gets word of the shootings and calls the Special Counsel to tell him that he's moving in on Reese. The Special Counsel tells him to get off the phone and go after Reese.
Reese tells Mira that Fusco will take her to the precinct where she'll be safe. She admits that she hasn't felt safe in years and she fled the country to try and find a safe place. Reese assures her that she's braver than she thinks, but Mira insists that she will put Petrovic away for good. Fusco arrives and Mira thanks Reese before leaving with the detective. Reese tells Finch to leave and he shuts down his computers leaves.
Moss asks Carter if she's ever lied with people that she's worked with or worked with a wanted criminal, and she says no to both questions. A man comes in and whispers to Moss. Once he leaves, Carter asks what it was about but Moss ignores her question and asks about her relationship with Cal. Carter admits that they see each other socially and Moss asks if she's aware of the ongoing investigations into Cal's activities.
Reese gets the disk from Mira's locker, just as Derek comes up behind him and asks what he's doing. When the manager demands to know what he's doing, Reese punches him unconscious and tells Finch that he's heading back to the library. However, Hersh finds Reese, takes his gun and phone at gunpoint, and takes him somewhere private.
Moss tells Carter that he's rescinding his offer of FBI employment to her. He refuses to explain why at first, saying it's confidential, but finally tells her to choose her company more wisely. As he leaves, Carter glances over at Cal. Meanwhile, Fusco brings Mira in and then goes to his desk. He tells Carter what happened and sits down. Meanwhile, the man from the hotel that bumped into Fusco comes in and says that he was mugged. Once the desk sergeant leaves him alone, the killer glances over at Fusco.
Hersh takes Reese to the kitchen and orders the staff out. He then demands to know who Reese works for and shoves him to the floor. Reese grabs a glass pitcher, smashes it into Hersh's hand, and tackles the man. They fight until Hersh grabs Reese and tries to shove his face into the stove. Reese breaks his grip and the two men grab knives. After a few stabs, Reese cuts Hersh just deep enough that he has 20 minutes until he bleeds to death. As he leaves, Reese asks if his employers would show him that kind of mercy.
Cal approaches Carter and suggests that he go to the botanical garden with Taylor. Fusco leaves to give them some time alone and Carter says that it might be too soon after all. Cal realizes that something is wrong and invites her to talk about it, but she says that she just needs time. Once she goes to the restroom to freshen up, the killer goes to Mira's room and garrotes her. Fusco and Carter return and Carter shoots the man.
Later, Finch and Reese watch the news in the hotel bar as Petrovic is taken away. Zoe comes in and she admits that she had some work to do involving the aviation conference. She congratulates them on taking down the escort ring. Derek has confessed and Zoe has been dealing with a number of clients who want to make sure that their names don't come up as clients. Reese explains that Finch bought the hotel to make sure that it's run properly. The new floor manager, Mira, comes in and tells them that the drinks are on the house. Once she leaves with Finch, Reese suggests that Zoe might work at the hotel. Zoe says that she's more of a freelancer and Reese says that he might even stick around for one more night. She takes the hint and figures that Reese can get the room... and he shows her that he already has the key for the penthouse suite.
In Washington, the Special Council receives a call from Hersh at the hospital. The killer says that he's on his way, unhooks himself from the IV, and walks out. The Special Council calls in his secretary, Ms. May, to draft a letter for him. Ms. May comes in with his suit... it's Root, who has been working for him for two months.