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Person of Interest Wiki
Episode Overview   Summary   POI   Cast and Characters   Crew    
  Person of InterestSeason 1 (Flashbacks in parentheses) Season 2 →
101Pilot” (Reese) 109Get Carter” (Carter) 117Baby Blue
102Ghosts” (Finch) 110Number Crunch 118Identity Crisis
103Mission Creep” (Reese) 111Super” (Finch) 119Flesh and Blood” (Elias)
104Cura Te Ipsum 112Legacy 120Matsya Nyaya” (Reese)
105Judgment 113Root Cause 121Many Happy Returns” (Reese)
106The Fix 114Wolf and Cub 122No Good Deed” (Finch/Ingram)
107Witness 115Blue Code” (Reese) 123Firewall
108Foe” (Reese) 116Risk

1x23 Firewall.jpg



Air dateMay 17, 2012

Running time43:46

Production code2J6223

Written byGreg Plageman
Jonathan Nolan

Directed byRichard J. Lewis


Images (43)

So nice to finally meet you, Harold. You can call me Root.

— Root

Season Finale. "Firewall" is the 23rd episode of season 1, and the 23rd produced hour of Person of Interest. It originally aired on May 17, 2012.


When a psychologist's number comes up, Reese must protect her from the crime organization HR while eluding capture by the FBI, who are closing in fast. Meanwhile, Finch receives an unwelcome visit from an old acquaintance.

Origin of the Title

Originally, a firewall was a fire-retardant barrier to restrict the spread of a fire. In the computer era, a firewall is a protection from outside access to a private computer or network.

Main Plot Points

  • Reese goes undercover as a client to protect this week's POI who is a psychologist.
  • Finch enlists Zoe's help.
  • Reese ends up trapped with Turing in a hotel with both an FBI team and a group of HR cops all dead set on killing Reese and Turing.
  • Reese gets Turing to Finch. She then identifies herself as Root. Finch learns that she paid for her own assassination knowing she would draw out Reese and Finch.
  • Alicia Corwin attempts to kidnap Finch in an attempt to destroy the Machine, but she is murdered by Root. Alicia acknowledges that as one of the seven original government personnel that know of the existence of the Machine, she has been on the run from killers.
  • Carter and Fusco learn about one another's relationship with Reese.
  • Simmons sees Fusco with Carter and Reese.

Episode Notes

  • A firewall is a piece of hardware or software that controls what data can move into or out of a computer system. It is designed to provide protection to a network or single computer against data from sources that cannot be trusted, notably the internet. It is these firewalls that hackers must get around to enter complex systems. The name derives from construction firewalls designed to keep fires out of buildings, and has become a metaphor for the mechanisms we use to protect ourselves from others. Root breached the Firewall around Finch.
Root-capture 1.jpg
  • The box around Caroline Turing is yellow, indicating her awareness of the existence of the Machine.
  • To celebrate Person of Interest airing on Netflix starting September 1, 2015, asked Jonathan Nolan and Greg Plageman to pick a few of their favorite episodes. Nolan picked "Firewall" because it was one of the greatest experiences he ever had working on anything, especially since Root is one of his favorite characters to write for.[1]

Production Notes

  • The episode began on May 17, 2012 and just after Donnelly escorted Carter into the NYPD Real Time Crime Center which had Reese and Root on a large monitor showing footage that occurred two hours before, then flashes back to two days earlier, where the action begins.
  • There are certain similarities between this episode and the “Pilot”:
    • Both episodes start with a flashback and end with Reese looking into a security camera. Moreover, the camera used by Reese to contact the Machine in this episode is in the same location as that used at the end of the “Pilot”.
    • The person of interest in both episodes is female and thought to be the victim. As it turned out, both women were actually the perpetrator.
    • Also, both episodes involved the POI hiring HR, except they were hired anonymously in this case, and Turing put the hit on herself while Diane Hansen ordered the deaths of other victims.
  • Before writing the episode, the writers knew they wanted to include HR but also they really wanted to add someone who would learn about the machine, but with malicious intent. Alicia Corwin wanted to shut down the Machine, but her reasons were more about her knowledge of the government coverup and the lives taken by the government in an attempt to secrete the Machine. The writers wanted a real villain. So two weeks before they were to begin shooting the episode, they decided they needed an archenemy, a Moriarty to their Sherlock, so as a last minute "Hail Mary," they rewrote it to include Root after an earlier episode.[1]

Bloopers and Continuity Errors

  • The date on Reese's phone shows May 17, although following the overall timeline in this episode, the hotel escape happens on May 18.
  • Zoe's clothes change color: at 5:30 am, when she calls Reese to tell him that she was going back to Turing's office, she's wearing a black dress and a white coat. A few minutes later, when she checks Turing's laptop and finds out that she's truly Root, she's wearing a red dress and a black coat.
  • Finch is stated to have rigged the cell towers so that only his cell phone would work. However, Reese, Fusco and Carter are shown to have working cell phones as well.


  • This is the only season finale to feature a full-length title sequence.
  • Fusco and Carter learn that they are working for the same person, Mr. Finch, and are able to work together to help Reese.
  • Reese's phone number is (917) 285-7362. Notably, this is the same number Finch later gives to Sameen Shaw in Relevance. Calling this number leads to Harold Wren's voice mail.
  • The NYPD Officer on the image to the right has a "CIB" collar pin. CIB  stands for Combat Infantry Badge and is issued by any branch of United States Armed Services. NYPD are allowed to wear military ribbons and CIB on their uniforms
  • With Reese in the backseat, Carter and Fusco drive by a huge billboard for the movie "Think Like A Man" which had Taraji P. Henson in a starring role.
  • Turing Test is a method of inquiry in artificial intelligence (AI) for determining whether or not a computer is capable of thinking like a human being.


  • "Just because you're paranoid doesn't mean they're not trying to kill you." (Reese)
  • "Define wrong person." (Finch)
  • "It's an article of faith for me that all criminals, however clever, eventually slip up." (Donnelly)
  • "Let's go make a mess." (Simmons)
  • "I have to say, Harold, we've been working together some time now, but you continue to surprise me." (Reese)
  • "He's like a professor, he's got glasses and a high dollar vocabulary." (Fusco, to Carter)
  • "Hello, detectives. I understand you'll have some questions but we're somewhat short on time." (Finch)
  • "He's in danger now. Because he was working for you. So you're going to help me get him back." (Reese)
  • "Trust is complicated Lionel. For example: I'm sitting in a police car with one cop who tried to murder me and another who spent six months trying to lock me up. So you'll forgive me if I take things one step at a time." (Reese)
  • "Well, we should all grab a drink together sometime. My treat." (Reese to Carter and Fusco)
  • "So nice to finally meet you, Harold. You can call me Root." (Root)
  • "She put the hit on herself. She was trying to lure you out into the open." (Zoe)
    "She wasn't looking for me. She was looking for him." (Reese)
  • ”Here, have some chocolate.” (Reese) “Will... will these help produce an adrenaline response?” (Turing) “No. But they taste good.” (Reese)


POI Quotes Here is for season one, episodes 1-12:

1. Finch to Reese: “I’m afraid the machine waits for no man.” - S01E08 "Foe"

2. Reese to Finch: “I am highly uncomfortable having you here. But I need a spotter.” - S01E04 "Cura Te Ipsum"

3. Carter to Finch: “Most people’s instinct is to look away.” - S01E01 "Pilot"

4. Finch to John: “A woman murdered in this room by her husband.” - S01E06 "The Fix"

5. Zoe Morgan to Reese: “I don’t understand you. And I don’t like things that I don’t understand.”

6. Reese to Carter: “In my defense, **** didn’t look both ways before crossing the street.”

7 Reese to Finch over the phone: “Guys who kill kids aren’t popular in jail.” - S01E02 "Ghost"

8 Some boy: “He also said that Vory are supposed to show respect to one another.”

9 Reese to Finch: “Some people the world can’t afford to lose.”

10 Reese: “The longest it’s ever taken me to break someone is 16 hours.”

11 Finch to Reese: “I breached the space-time continuum.” - S01E10 "Number Crunch"

12 Reese to Finch: “What I said about our guy being boring, I take it back.”



Person of Interest Firewall Season 1 Finale Ending HD

Ending scene