|Episode Overview||Summary||POI||Cast and Characters||Crew|
|← Season 2 Person of Interest — Season 3 (Flashbacks in parentheses) Season 4 →|
|301 “Liberty”||309 “The Crossing”||317 “Root Path (/)”|
|302 “Nothing to Hide”||310 “The Devil's Share” (Multiple)||318 “Allegiance”|
|303 “Lady Killer”||311 “Lethe” (Finch)||319 “Most Likely To...”|
|304 “Reasonable Doubt”||312 “Aletheia” (Finch)||320 “Death Benefit”|
|305 “Razgovor” (Shaw)||313 “4C”||321 “Beta” (Grace)|
|306 “Mors Praematura”||314 “Provenance”||322 “A House Divided” (Collier)|
|307 “The Perfect Mark”||315 “Last Call”||323 “Deus Ex Machina” (Collier)|
|308 “Endgame” (Carter)||316 “RAM”|
|“||You took the wrong information, you twisted it. You're supposed to lock up the criminals, not create them.||”|
— Peter Collier
When an unknown entity prevents the Machine from seeing the full picture of an impending catastrophic event, it sends the team five separate numbers to help them piece together the bigger picture. Meanwhile, Root’s team of hackers arrives in New York.
Origin of the Title
The episode's title draws from Abraham Lincoln's "House Divided" speech from his unsuccessful early campaign for the Illinois Senate. In it, he warns of the division, and possible downfall, of a country which allows slavery in some states but not on others. Lincoln drew from the Gospel of Matthew (12:25), which similarly extolled that a house, city or kingdom divided within is bound to fail. In this case, Finch and Reese have been divided, disrupting the balance between the two and the team's operations.
Main Plot Points
- The Machine detects an imminent threat but is unable to determine when or the nature of it. The Machine then begins tracking its assets to re task them to research.
- Reese and Shaw chase a Decima Technologies agent named Otto onto a roof to question him about the location of Finch. However, Otto commits suicide instead. Root arrives and explains.
- Greer and Finch meet face to face and Greer tells Finch that they are there to talk about the future. Greer sees Samaritan as the future and Finch, as the father of AI as a threat to Samaritan as he is the only one who can destroy it.
- Root steals the keys to Otto's car from his body and then removes his car's satellite radio to use its GPS to find out where he's been. Root then reveals her team to Reese and Shaw: Jason Greenfield, Daniel Casey and Daizo. Root explains that they have been stealing "contraband" in the tri-cities and asks to use Reese's safe house before tasking Shaw to go to the Carlton Hotel with a satellite phone.
- Greer meets with Senator Ross Garrison who tells him that he will be meeting with the Presidential advisor about giving Samaritan the NSA feeds permanently.
- Shaw monitors the Carlton Hotel and after spotting Secret Service agents and a government vehicle, takes a picture of the license plate. The Machine analyzes the picture, detects a threat and immediately issues five irrelevant numbers to Reese the first of which Root recognizes: Control. The group suspects that Control is planning something.
- Garrison works to convince Control to accept Samaritan as a replacement for the Machine while Control is unhappy with the idea of paying for information from the people that stole Samaritan from her in the first place. Control agrees to look at the results of the beta test.
- General Kyle Holcombe and Manuel Rivera, the Presidential adviser arrive.
- In the coffee shop, Root and Reese approach the man the Machine has them watching who Reese notes has a P90. The man opens fire before Reese shoots him down. From his license, the two discover that the man is Niall Jacobs and they find a thumb drive upon which is a Stuxnet variant computer virus. Reese realizes that Jacobs is Vigilance but Jacobs doesn't know anything of Vigilance's plan beyond his own role in it. Shaw then warns them that Vigilance has arrived at the hotel.
- Root gets a call from Greenfield and Casey who tell her that the virus targets micro transmitters in the power company. Root tells Reese to help Shaw while she goes off on her own. Shortly afterwards, all of the power in New York goes out.
- In Greer's hideout he and Finch discuss Greer's experiences as a child during the London Blitz. Greer finally explains that he wants a leader for the world who is not corrupt and is worth following: Samaritan who will make decisions by logic not greed.
- With Shaw and Holcombe covering them, Control's group attempts to make a run for it only to be ambushed by Collier and Vigilance. Vigilance is able to kidnap Control and Rivera alive while Holcombe is killed. Two Vigilance operatives corner Shaw but Reese arrives in time to take them down. As they realize that Vigilance must have something else planned due to them taking Control and Rivera alive, they come face to face with Hersh.
- Root makes her way into New Jersey in a truck with her team and Greenfield tells her that Daizo and Casey are nearly finished with the Samaritan servers.
- Garrison meets with Greer at his base and warns of the threat of Vigilance. Greer tells him its too late to flee as Collier and his men arrive and capture them. Collier recognizes Finch from the last time they met and takes him captive as well to get answers to the questions he never got to ask the last time.
- Root stops her truck and her team informs her that the Samaritan servers are ready. Root then gives the team new identities and tells them that their jobs are over and an approaching car will take them where they need to go. While Casey insists on helping, Root tells them that the Machine has calculated that they will all die if they go together but separate they have a slightly better chance. She then points to a nearby building and states that Samaritan is inside.
- Hersh leads Reese and Shaw to Decima's base but they find it deserted. On a view screen in the room Finch was held in, the three witness a transmission made by Collier where he announces that he is placing Control, Finch, Rivera, Garrison and Greer on trial as well as the US government to expose the truth.
- In 2010, Peter Collier, then going by his real name of Peter Brandt visits his brother Jesse and discusses his aspirations to become a lawyer and eventually a prosecutor as well as Jesse's impending one year anniversary of being sober. As they talk, two FBI agents arrive with a warrant for Jesse's arrest but refuse to specify the charges, citing a national security exception.
- On March 10, 2010, Collier meets with US Attorney Langdon about Jesse being denied legal counsel and being held without charges. Collier insists that Jesse is not a terrorist and Langdon finally shows Collier pictures of Jesse meeting frequently with Aziz Al-Ibrahim, the cousin of an Islamic terrorist who had tried to blow up a US embassy. Langdon suggests that after Jesse hit rock bottom, Aziz turned him into a terrorist and states that "surveillance doesn't lie."
- Jesse ultimately kills himself in prison and Collier and his ex-sister in law hold a memorial for him and grieve what happened to him. At the memorial, Aziz approaches Collier and reveals that Jesse spent so much time with him as Jesse was his AA sponsor. Aziz had no connection to his cousin's terrorist activities and describes him as a distant relative who caused his family a lot of trouble. Aziz gives his sobriety chip to Collier so that he will always know that Jesse saved someone's life.
- Collier visits the US Attorney's office to find Langdon gone and a woman in his place. Collier tells her about how Jesse was not a terrorist and was instead connected to Aziz through AA. The woman is unrepentant about Jesse's death, saying that innocent people don't kill themselves. Collier tells her that Jesse committed suicide as he lost hope and accuses the government of creating criminals instead of catching them and being responsible for his brother's death. As Collier leaves, he gets a text message offering him answers.
- As Collier's kangaroo trial comes on air, the television set briefly features the classic Indian-head test pattern. This image was used on television stations from the late 1940's until television stations began to broadcast 24 hours a day in the 1960s and 70s. It appeared following the end of a station's nightly program and the national anthem, while the station was still transmitting. It would reappear in the morning when the station began transmitting, but before it signed on and began its morning programming.
- The weapon that Niall Jacobs uses in the bakery is a FN P90 Personal Defense Weapon manufactured in Belgium and very popular with law enforcement agencies around the world, especially the U.S. Secret Service. The FN P90 holds 50 rounds of ammunition. With the video of the bakery shootout slowed to 25% of it's original speed, the viewer can count exactly 50 bullets having been fired before Reese shoots the gunman.
- At one point Daizo, Jason Greenfield and Daniel Casey are shown having a yellow box which means they know about the Machine.
Along the way, Person of Interest became something more. According to Buzzfeed, "It became prescient, for one thing: The web the show had fictionally spun in which the government, often in collusion with corporations, is watching and listening to us, turned out to be almost exactly what Edward Snowden’s leaks revealed to be true. While Person of Interest still has the spine of a case-of-the-week procedural, it has deepened into an acutely paranoid, multi-layered story about emotionally damaged, well-funded vigilantes (who kill frequently). The structure of the show also shifted in Season 3; Carter (Taraji P. Henson), Finch and Reese’s police ally who also became a friend, was killed, and Shaw (Sarah Shahi) and Root (Amy Acker) — both of whom may be clinically insane — joined the gang. In Nielsen’s season-to-date ratings, Person of Interest draws 14.2 million viewers. That’s down marginally from last year when it aired on Thursday nights at 9 p.m., but it’s still the fifth most-watched scripted show on network television." 
Bloopers and Continuity Errors
- Peter Collier's real last name "Brandt" may be a reference to Molly and Joseph Brant, two prominent figures in the American Revolution.
- "Why do these Decima guys keep killing themselves?" (Reese)
- "I want to talk about the future. And who more qualified for that conversation than the father of artificial intelligence?" (Greer, to Finch)
- "You're that government hitman that made me pull out my molars!" (Casey, upon seeing Reese)
- "Having built something significantly smarter than myself how could I possibly anticipate its evolution?" (Finch)
- "I built the machine to save lives. But how could I be certain that it wouldn't one day determine that all of humanity was irrelevant?" (Finch)
- "It's pure hubris to think that you could control something so powerful." (Finch, to Greer)
- "And while the public shouts from the rooftops about their civil liberties, they do so under the protective bubble of the very program of which they are railing against, the one that saves them from terrorist attack every single day." (Control)
- "Ma'am, long time no gunfire." (Shaw, to Control)
- "I can't believe what I'm about to say. I'm here to rescue you." (Shaw, to Control)
- "How often alliances shift in times of war. Not that those alliances ever truly exist. They're an illusion, like seeing a sunset in a sky of flames." (Greer)
- "Just 'cause you've stopped listening to the numbers doesn't mean they've stopped coming." (Reese, to Hersh)
- "That is the most important man in the world senator, the father of the new age." (Greer, about Finch)
- "Boys, meet Samaritan." (Root)
- "Court is now in session." (Collier)