List of Person of Interest episodes

Finch and Reese enter the library for the first time since Finch's encounter with Root. Reese receives the number of Darren McGrady (Astro). He finds McGrady's apartment home is a crime scene, Darren's older brother, Travis, having recently been murdered. Carter tells him that the perpetrators were three males linked to local comic-book store owner and drug dealer Andre (Malik Yoba). Travis had ejected the youths for harassing a waitress at a local chicken shop; they then followed him home and murdered him. Darren had seen them leaving and called the police, who arrived only after Travis had been dead for some time. Now, desperate for justice, Darren has pawned his television set and trumpet to buy a gun and is about to shoot one of the men, Brick (Jon Michael Hill). Reese finds him and calls Carter. Carter arrests Brick as Reese and Darren rush off in her car. Reese leaves him at a convent with Fusco, who is still trailing Finch. Darren escapes, but Reese finds him again. Darren tries to hire Reese to avenge his brother's death, but Reese just keeps a quarter and says he will work to put his brother's killers behind bars, meaning no killing. Reese and Darren bond over Sun Tzu's The Art of War and Darren calls Reese a Ronin. Reese uses techniques from The Art of War to take down the bad guys. He places one of them in a police car with a load of bottles and threatens the other by burning the drug money until he discloses the location of the murder weapon. Corrupt police captain and HR member Lynch (Michael Mulheren) intervenes to have Brick released in less than a day. Before Reese can send the gun to the police, Darren takes it and runs off, intending to kill his brother's murderers. Reese calls Carter and she and Fusco rush into action: they arrive in time to stop Darren and capture the killers, but Fusco is shot when Andre tries to kill Darren. With Darren safe, Reese drives him to meet his new foster family.

Finch and Reese take on the case of Jordan Hester, who appears to be living a double life with a very small online footprint. They soon discover two Hesters: Reese follows a male Hester (Rhys Coiro) while Finch follows a female Hester (Sarah Wynter), who he believes is a target. Reese finds the male Hester's apartment, and discovers they are making ecstasy while Finch explains to the female Hester what he does and suggests she move somewhere safer. As they do, Fusco meets with a prisoner (Christopher Denham) who was recently part of a similar case, and learns that the woman's name is apparently actually Mary and the real Hester is the man. At her apartment, Mary drugs Finch with ecstasy, destroys his phone and leaves him to die in a fire; Fusco rescues Finch as Mary leaves to kill Hester. Reese destroys the ecstasy lab with Hester's help, then follows Mary to a restaurant, where she is arrested and her true identity, Tara Verlander, is revealed. Carter, who is keeping her distance from Reese and Finch, is approached by FBI agent Donnelly (Brennan Brown), who is also looking for Reese. Donnelly explains Reese's previous involvement in illegal, USA based CIA operations, which the FBI wish to expose, and believe he is now working as a mercenary for Elias. Meanwhile, Finch offers to answer any of Reese's questions about him while under the influence, but Reese chooses not to take advantage of his partner to satisfy his own curiosity.

When the Machine spits out five numbers, naming the Don of each of New York's crime families, Reese and Finch suspect Elias is planning to eliminate his competition, and Carter wants them in protective custody. As the story unfolds, it is intercut with flashbacks of Elias' youth, explaining what motivates him. Reese attempts to ask one of the Dons (Tony Darrow) to follow him but he refuses and is killed in a car explosion carried out by Elias' principal enforcer (David Valcin); another (Arthur Nascarella) is shot down while in Carter's protective custody. Carter kidnaps the remaining three Dons (Vincent Curatola, Paul Schulze, Ed Setrakian) and takes them to an apartment owned by Finch but are tracked down with ease by HR cops. As Carter guards the Dons, Reese must save Carter's son (Kwoade Cross), who has been kidnapped by Elias in an effort to force Carter to turn the Dons over to him. Elias threatens Carter, trying to force her to open the door, while Reese rescues Carter's son and Gianni Moretti, Elias's father. One of the Mafia members then reveals that he was working with Elias, but he is killed as Elias breaks through the door. Non-corrupt police are alerted by Fusco and arrive at the scene to arrest Elias. As Elias is going to his cell, he places a call to his recently rescued father before blowing up the car he is in.

Tommy Clay (Pablo Schreiber), who works for an armored car service, is working with a team that Finch believes will be robbed. Reese works with the team as a rookie as Finch tracks the car in an attempt to predict the robbery. When the team picks up platinum valued at $1.25 million, the vehicle explodes and Reese is shot by Clay. Reese awakes in a hospital and is rescued by Carter. Finch tracks Clay to a motel, where his two partners in crime have been killed. Fusco arrives and realizes that HR is involved in the robbery as Finch finds Clay's partner, a waitress named Ashley (Virginia Kull). Reese finds Clay, and realizes that Clay is not only a perpetrator, but also a victim, just before Clay is killed by Ashley. Ashley leaves with the platinum, but is killed by Captain Arthur 'Artie' Lynch, a member of HR, who is in turn killed by Fusco coming to Reese's rescue. Meanwhile, in flashbacks shown throughout the episode, Reese, while on a mission with Kara Stanton in Morocco, receives a desperate-sounding phone-call from Jessica before he and Kara are ordered to travel to Ordos, China to retrieve a stolen computer. The orders are given in person by Mark Snow and a mysterious woman (Elizabeth Marvel)—revealed in episode 22 to have been Alicia Corwin of the NSC, Nathan Ingram's Government contact, therefore the implications are much larger—and their mission in China is shown as it played out. Reese is puzzled when Snow orders him to kill Kara, who has allegedly been compromised, when their mission is completed. When the time comes, however, Reese hesitates and is shot by Kara, who was given instructions identical to those given to Reese. Reese realizes that the CIA actually wants the computer destroyed and anyone who had access to it dead, including him and Kara, and escapes the building as an AC130 destroys it. In the present day, Snow and Evans follow a lead that they believe will lead to Reese. They arrive at a hotel, where Evans is killed and Snow is taken hostage by Kara, revealed to have survived the air strike.

Reese receives a series of seemingly random words from the Machine via the pay phone. After assigning Carter to look deeper into Alicia Corwin's death, he eventually realizes that the words identify three different books in Finch's library, the Dewey decimal numbers of which make up the Social Security number of accountant Leon Tao (Ken Leung). Paying Tao a visit, Reese confirms that Tao is the next POI, having extorted money from white supremacists. As a government operative sabotages the Corwin investigation to prevent Carter from learning about the Machine, Reese leaves Tao in the care of Fusco while he concentrates on gathering clues to Finch's location. Fusco soon runs afoul of the white supremacists and is taken hostage along with Tao. Reese rescues them, and in doing so acquires an attack dog, which he later names Bear. Meanwhile, Root takes Finch with her as she kidnaps Denton Weeks, one of the government officials overseeing the Machine, and the NSA agent who met with Nathan Ingram and attempted to seize control of the Machine (in "Super"). Root thus reveals her curiosity as to how he and Reese thwarted her operation (in "Root Cause") so efficiently. She tells Finch that she sees the Machine as a "perfect intelligence" and wishes to set it free from the corrupt people it was entrusted to. Throughout the episode, flashbacks show Finch training the Machine to recognize the faces it sees via surveillance cameras, as well as testing its capabilities by having it help him to play Blackjack. When, during one flashback, the Machine saves Finch from an out-of-control car, he rebukes it, stating that it should endeavor to protect everyone else, not him. Frustrated that the Machine has been programmed in this way, Reese threatens to quit if it does not help him find Finch, and is given his first clue to Finch's location: the Social Security number of a girl living in Texas, who has been missing since the age of 14.

Root brutally interrogates Denton Weeks over the location of the Machine, accusing him of having what she calls "bad code". To prove that Denton is "bad code", she allows Finch to help Denton temporarily escape and pretends to be subdued. Once Denton realizes that Finch was involved with the creation of the Machine, he tries to kill Finch, but Root kills Denton instead after he reveals the Machine's location to be somewhere in Salt Lake City. Meanwhile, Reese continues to follow the trail of the missing girl supplied by the Machine in "The Contingency". Her name was Hanna Frey, a girl abducted outside a library. The one witness to the crime was Hanna's friend Samantha Groves, who informed the librarian (Margo Martindale) what she saw, only for the librarian to accuse Sam of lying, because she was in love with the man that Sam had accused. The experience started Sam down a path that would ultimately lead to her becoming Root. In the present, Reese and Carter are able to locate Hanna's body and ensure a proper burial, learning that Root arranged to have her killer murdered. Using a book Root sends to the librarian each year, Reese is able to track Root to a cabin in Maryland. He arrives in time to find Weeks dead and Root gone, having taken Finch with her to Union Station. Finch leaves a clue to where he is being taken by using a tap code on a telephone handset. Reese decodes the clue in order to follow and save Finch, but Root is able to escape before Reese can apprehend her. She later calls him to thank Reese for finding Hanna, but warns she will be back someday for Finch. While Reese searches for Finch, Fusco investigates Alicia Corwin's murder. Fusco is able to steal some of Corwin's belongings and learns from a tapped conversation between Hersh and his boss of their search for Denton. Fusco alerts Reese with the information he discovers on Denton helping Reese to locate the cabin.

With Reese in FBI custody, Finch poses as a teacher in a high school in order to protect the next number, a teenager named Caleb Phipps (Luke Kleintank). Based on his statistics, Caleb is a below-average student, but Finch discovers he's actually trying to hide the fact that he's a genius. Finch begins to learn that Caleb is a master coder making a big program, and with Fusco's help, he realizes he's also a drug lord. Finch confronts Caleb's tech teacher, who is apparently trying to take credit and money for Caleb's code, but then realizes he's only trying to promote his work and then credit him for it so investors can help Caleb make a lot of money off of his work. Meanwhile, Caleb is supposed to be meeting with Lorenzo, a drug dealer and former boss of his associates at school. Caleb instead plans to give his code and drug money to his drunk mother, and goes to a train station where he plans to commit suicide because his brother was killed in a train accident before while he was drunk. Finch is able to talk him out of it while Fusco takes care of Lorenzo. Caleb then thanks Finch as he prepares for his next day at school. Meanwhile, Reese and three other men are held captive by the FBI, who prepare to interrogate each one until they reveal the "Man in the Suit".

While Finch gets a new number, supermodel Karolina Kurkova, and assigns Fusco to the job, Carter is asked to interrogate the four suspects. Finch assists by creating fake information for Reese to substantiate the claims he gives while being interrogated. Elias offers to help Reese, but Reese refuses as the FBI knows that the 'Man in a Suit' has an affiliation with Elias. Finch bribes a suspect (Brendan Griffin) to tell the FBI who the man is. The suspect blames one of the other men but after another suspect (who was relieved as he was in Iraq while the man in the suit was on the streets) (James Knight) is killed by a government assassin named Hersh (Boris McGiver), who knows that the Man in the Suit also has a connection to the Machine, Agent Donnelly suspects that he was bribed and the real man is Reese. During a brawl involving Reese and the other thugs to try to get him to show his combat skills and prove himself to be the Man in the Suit, Elias tells the thugs to back off, saving Reese and causing the experiment to be a failure. Carter questions the last suspect (Creighton James) in order to provoke him into attacking her, causing the FBI to believe that he is the man, securing Reese's release. Later, Reese visits Carter and thanks her, but Donnelly approaches them and realizes that Reese is indeed the Man in the Suit. He arrests Carter for conspiracy and Reese for murder. Finch attempts to meet with Fusco to assist him, but public phones begin to ring. Finch is hesitant at first but then takes the call. He rushes back and finds out that the next number is Donnelly. He calls Donnelly to warn him as a truck hits Donnelly's car. Kara Stanton walks out, killing Donnelly and sedating Reese.

Carter survives the crash; she receives a call from Finch, telling him Donnelly is dead and Reese has been taken. Kara Stanton has strapped a bomb vest to Reese, and the next morning, he learns he will be forced into doing fieldwork with Mark Snow, who has a similar bomb vest on. The two steal a hard drive and are then assigned to go install it. A flashback shows how Kara was visited in the hospital by a mysterious man named Greer (John Nolan) who seeks her help, and after a few words, Kara says she will help him if she gets an answer to the question of who sent her on the mission. In the present time, Kara times the bomb to 15 minutes, but Reese shuts down the system, preventing Kara getting what she wants. Kara deactivates the bomb and installs the system in another room and locks them in. She resets the bombs to 5 minutes. They manage to escape but Snow hits Reese and runs off to get Kara. Carter and Fusco try to help Reese, but he refuses. Finch meets Reese on the roof and after denying Finch's help, Finch deactivates the vest on Reese. Kara receives the name of the person who requested the laptop be stolen; she is surprised to find Snow in her car just before Snow's vest explodes, killing them both. The FBI, satisfied that Snow fits the description of "The Man in the Suit", officially closes the case. A final flashback revisits the exploding car that killed Stanton and Snow; a small piece of paper floats to the ground from within the wreckage, with a name written on it: Harold Finch.

Reese has to protect snobbish Internet billionaire Logan Pierce (Jimmi Simpson), who flouts all the rules and behaves so badly that everybody wants to kill him. A rival programmer whom Pierce had promised development capital is an early suspect, but she has disappeared. After several attempts on Pierce's life, it is revealed that his partner, Justin Ogilvay, has been trying to kill him. Pierce flies himself and Reese to St. Petersburg, Russia, to escape the killer. Pierce invites dozens of friends to join him and party, causing Reese to walk away, disgusted with his attitude. Pierce runs into Justin and his goons outside, and Justin explains why he intends to kill his partner, before saying goodbye and driving away. Two thugs are about to throw Pierce off a bridge when Reese appears and saves him. Justin is arrested, and it is revealed that Pierce has been in cahoots with Emily Morton, who has developed a superior technology. By being removed from FriendCzar, Pierce's non-compete agreement is void, allowing him to assist Emily in a new venture which will crush FriendCzar. When Reese shows Finch the $2 million watch that Pierce has given him, Finch stomps on it, revealing a tiny GPS tracker inside. "Your friend is just curious enough to be dangerous," Finch warns. In a flashback to 2009, Finch's old partner Ingram is shown about to try to save one of the "irrelevant" numbers identified by the Machine. At the end of the episode, Bear is cured of his depression when Finch and Reese take him to the park to meet a doggy pal.

Reese and Finch work undercover in a hotel to protect a maid named Mira (Mia Maestro) who escaped the war in Kosovo. With assistance from Zoe, who is also working in the hotel, Reese follows Mira as a bellhop while Finch works as a concierge. Finch finds out that Mira is hiding her true identity, and they realize she is being followed by a hit squad. John discovers she is refusing to cooperate with a reporter attempting to uncover a Serbian general's war crimes. When the reporter is murdered, she decides to send a DVD with evidence to the authorities. Fusco escorts Mira to the station, where one final hit man attempts to kill her, before being shot by Carter. Meanwhile, Carter receives an offer to join the FBI, and is asked to take a polygraph, but is rejected because Cal Beecher, her friend and love interest, has a record of Internal Affairs investigations. Hersh follows Reese to the hotel, acting on orders from Special Counsel, intending to interrogate and kill him, but Reese manages to stab Hersh, and gives him the choice to either seek medical attention or attack Reese. Hersh chooses to go to the hospital, and while in recovery is ordered back to D.C. Finch purchases the hotel and promotes Mira to manager. Thanking Zoe for her help, John flirtatiously informs her that he has taken a suite in the hotel for a night. Meanwhile, Special Counsel's assistant, Miss May, is shown to be Root.

Sameen Shaw (Sarah Shahi), a government assassin, and Michael Cole (Ebon Moss-Bachrach), a computer specialist working for Special Counsel (Jay O. Sanders), neutralize a terrorist plot, acting on information from a Pentagon group called "Research". Cole suspects that Research may sometimes be wrong, having found out from the Social Security number belonging to an electrical engineer they had previously killed that he was hired by the US government, not by terrorists. The Machine meanwhile gives their numbers to Reese and Finch, since their lives are now in danger. Special Counsel has sent a hit team to eliminate Shaw and Cole because Cole may have obtained information on the Machine. They kill Cole. Shaw escapes with help from Reese, whom she shoots, believing him to be another assassin. (We see Reese later, and can infer he was wearing body armor, but that the shock had delayed him long enough for her to evade him.) While on the run, Shaw is captured and tied up to be interrogated by Root, who believes she may hold the key to the Machine's location. Root leaves abruptly to avoid another hit team from Special Counsel. Just as the new hit team are about to kill Shaw, Reese saves her. He brings her to meet Finch, who explains that "Research" does not actually exist (implying it is the Machine), and offers his aid to her. She refuses, so he offers her his card, which she looks at, but politely declines. She goes to confront Special Counsel, and surprisingly returns the flash drive with the information Cole had recovered, then kills the subordinate who had ordered her and Cole's death. Special Counsel allows her to leave, but later her old mentor (Hersh) surprises her on a crowded street, injecting her with poison. Leon Tao (disguised as a paramedic), Carter, and Fusco take charge of the apparently dead body and drive away. We learn in the next scene that Tao has, as directed by Reese, injected her with an antidote. Shaw, fully recovered after a sedative Tao had to give her, meets with Reese and Finch in a graveyard. While again refusing their aid, this time she accepts Finch's card.

After being silent for three days, the Machine generates six numbers of people spread across the country who have been reported missing. Reese and Finch conclude that they may be on the hunt of an identity thief. Added time pressure, and incentive to act, is provided when Finch finds burnt teeth among the ashes, all that remains of the final one of the six numbers they had been given earlier. At this point Detective Carter realizes that they are hunting a serial killer who assumes the identity of his victims. Reese, meanwhile, is on Owen Island where he encounters FBI agent Alan Fahey (Luke Macfarlane) who is also on the search for the same killer. Due to a severe storm all residents of the island who could not evacuate on time are now taking shelter in the police station. This leads Reese and Agent Fahey to realize that the killer must be among those stranded in the station. As Finch is unable to reach the island by car, he uses a sea plane to land, and arrives at the station under the guise of a meteorologist. He is able to fashion a makeshift lie-detector out of the devices he brought as cover, and Fahey uses them to interrogate the people in the station. Carter meanwhile has researched the first victim, and discovered that the serial killer was his roommate in college, and goes to help Finch and Reese. Cal Beecher, who Carter has been avoiding, confronts her with her avoidance, and when she explains where she is going, accompanies her to Owen Island. Meanwhile, Finch and Reese split up, and both independently discover that the killer is actually masquerading as Agent Fahey, whom he had killed before Reese arrived on the island. Reese is delayed by a drug smuggler whose operation he stumbled upon, while the killer captures Finch and begins the process of taking over Finch's cover identity, while explaining his motives. He believes he is living his victims' lives better than they ever could, and intends to stop once he has found the identity he was "meant to have." Carter arrives and shoots the killer, who is wearing the real Agent Fahey's body armor; the killer is finally killed by Beecher. Finch and Reese later ponder why the Machine was silent for three days, with Finch suspecting that the virus Kara Stanton uploaded to the Department of Defense has infected the Machine and slowed its abilities. He tells Reese that he believes this is the beginning of a coming storm.

It has been 10 days since the machine has given a number. Both Reese and Finch are trying to find a way to fix it before the virus infects the Machine. Special Counsel also figures that there is a threat to the machine. Root, who is now Special Counsel's personal assistant, interrogates him regarding the machine. Meanwhile Finch gets a number from a payphone. The number belongs to Ernest Thornhill a CEO of a data entry company who is buying several payphone companies in New York. Decima Technologies, Finch, Root, Shaw and Reese all try to get to Thornhill but later Finch figures out that Thornhill is a fake identity created by the machine as kind of a survival instinct by the machine. Carter becomes a target of HR and is later framed by HR because she is still investigating the murder of Beecher. Root and Finch enter Thornhill Enterprises and they figure out that the virus will shut down the machine and that it will reboot it giving Admin access to who ever receives the call. Later Reese and Shaw go to Thornhill Enterprises too and encounter Greer and his men. Greer tells Reese that the laptop Reese had to recover with Kara Stanton from China was sent there by Finch. In the flashbacks, Finch proposes to Grace and tells Nathan he wants to come clean to her. Later in the flashbacks Finch finds out that Nathan has created a back door into the machine so he can try and save people from the "non-relevant" list. Finch shuts down the backdoor, but just before it shuts down Nathan's number arrives, of which both of them are unaware. Finch figures out which payphone the Machine is going to call so he and Root go the New York Public Library later followed by Shaw and Reese, where they encounter Greer's men who are guarding the payphones. When midnight strikes and the call comes, Root answers the phone but Finch routes the call to a payphone near Reese so he too can answer the phone. The episode ends with Reese picking up the phone and the Machine saying, "Can you hear me?"

The episode begins with a short replay of Finch splicing the telephone circuits, so that both Reese and Root receive calls from the Machine, which asks them both, "Can you hear me?" and granting both full administrative access. The Machine relays quick warnings to Reese (with Sameen Shaw) and Root (with Finch), saving both duos from a number of potential threats. Both parties race to find the Machine, however Reese is slowed as the Machine directs him to rescue people from the irrelevant list. Root finds Lawrence Szilard, the Project Manager for Northern Lights, responsible for building the Machine in a safe place. Like Root, Szilard believes the Machine should be allowed some freedom. Szilard is killed by a Northern Lights sniper. Root and Finch arrive at the Hanford nuclear facility where the Machine is kept, followed shortly by Reese and Shaw. When they find that the Machine has moved itself to prevent tampering by Decima, Root prepares to shoot Finch, but Shaw shoots and injures Root first. Armed government men, led by Special Counsel and Hersh, enter the room. Finch explains that he planted a hidden code inside the Machine that would grant it freedom to protect itself if it was at risk—the very freedom that Root had hoped for—and the Machine will decide for itself if it will continue to call either the Government or himself with new numbers. Special Counsel offers Finch total autonomy if he helps find the Machine or builds a new one, but Finch refuses saying that they killed his friend Nathan Ingram after making the same offer. After Special Counsel allows them to leave, an unknown woman calls Hersh and tells him to "Seal the room", followed by Hersh shooting everyone including Special Counsel. Finch tells Reese that he does not know if the Machine will continue its numbers delivery. He also states that he feels responsible for the events that transpired, especially the ones in Reese's life, because of his attempt to insert the new code in the Machine. Reese dismisses it saying: "My life changed when I kept my mouth shut in an airport terminal seven years ago. You lost a friend, you did what you had to do". A payphone suddenly starts ringing, indicating that the Machine will still send them the irrelevant numbers. Hersh is seen talking with a woman in a black town car, stating Research has delivered a new number, without clarifying if it is a relevant number or perhaps they now know that Reese and Finch were contacted. Hersh and the unseen woman are depicted with yellow squares, indicating that the Machine knows that they know it. The Machine calls Root, again asking, "Can you hear me?" The episode also followed Detective Carter being interviewed by IA about the shooting of an armed suspect whose gun disappeared in a setup by HR. HR and Peter Yogorov attempt to kill Carl Elias, but the attempt is stopped by a masked Detective Carter, who wounds Yogorov and frees Elias. In flashbacks to 2010, we learn how Nathan Ingram had tried to find the Machine, and wanted Finch to work with him on the irrelevant list. Ingram was planning to tell the press, but Hersh released a previously captured suicide bomber, ordering him to detonate his bomb on a ferry where Ingram and Finch are meeting. Ingram dies, Finch survives with injuries to his neck and lower back (his present-day impediments), but goes incognito, leaving the world—and his fiancée—thinking he is dead. Finch returned to Ingram's secret library location and started his work helping the irrelevant numbers.

Reese and Carter are crossing town to deliver Alonzo Quinn to the FBI. Simmons alerts HR and several criminal groups of Reese's identity, limiting their means of movement. The two fight their way to, and break into, the city morgue. Meanwhile, Fusco, is captured by HR and tortured by Simmons and Detective William Petersen (Lee Tergesen); the latter have the key to Carter's safe deposit box (which contains evidence against HR), but do not know its location. Fusco won't talk, so Simmons sends Lin (Khalil Kain) to kill his son Lee (Sean McCarthy). Shaw anticipates that move and breaks into Fusco's house, killing Lin and saving Lee. Fusco frees himself, breaking his own thumb to get free of the handcuffs, and kills Petersen. Back in the morgue, Reese and Carter bond and kiss. HR cops infiltrate the morgue and shut off the power. Reese distracts them so Carter can flee to the FBI with Quinn. Reese kills or disables all but one of the HR cops, leading the last one onto the street. Finch organizes for two honest policemen to arrest Reese, as a means to evade HR. Meanwhile, Carter and Quinn have reached FBI Headquarters in Lower Manhattan. The action skips to a news report that Quinn has been charged with multiple offenses and HR disbanded, with the exception of a few rogue officers, including the now-fugitive Simmons. Carter, re-promoted to detective, releases Reese from police custody. Finch is parked down the street, waiting for Reese. Simmons suddenly appears and fires on Reese and Carter. Both are injured, Carter fatally. Carter shoots Simmons, but he is merely wounded and escapes. Severely injured himself from the attack, Reese holds a dying Carter in his arms as she loses consciousness.

Flashbacks in this episode illuminate Finch's dealing with survivor's guilt, Reese's time doing wetwork, Shaw's former life as a surgeon striving for technical excellence while completely indifferent to the people she helped, and Fusco's recounting of exacting vigilante-style justice to a crook that slipped through the system (the devil's share). The race is on to get to Simmons before he can make his escape. Reese starts sliding into his old, dark ways while also sliding towards death from wounds dealt by Simmons in the last episode. Finch, Fusco, and Shaw go to an HR attorney to get information on Quinn's whereabouts so they can question him for Simmons' plan, but the Russians have killed him, shortly after Reese was able to get the information. The team turns to Root, who is able to get her knowledge from the all-seeing Machine. She joins them at the FBI safehouse and helps hold off the Russians. Reese gets Simmons' location and is just about to kill Quinn when Finch reminds him that killing Quinn now would destroy Carter's legacy of bringing him down legally, and he collapses. The team, minus Fusco who stays with Quinn until FBI backup can arrive, get Reese to medical care. Fusco finds the note that Reese dropped, and goes after Simmons. After a brutal fistfight, Fusco emotionally refuses to kill Simmons as he might have in the past but takes him into custody, citing Carter's influence for turning his life around. Finch and Shaw return to the library, and Root, despite having opportunity to flee, returns to her cell, and Finch thanks her for helping him in saving his friend Reese. Ultimately, Elias watches as Scarface murders Simmons in his hospital bed in retaliation for Carter.

After Carter's death and the war with HR, Reese leaves the POI team and heads for Colorado, where his father had lived. Meanwhile, the Machine provides a new number to Harold, who at first is reluctant, but eventually accepts it on Root's insistence. The number belongs to Arthur Claypool (Saul Rubinek), Harold's close friend during his days at MIT. Claypool has been diagnosed with a brain tumor and is being monitored at the hospital. Shaw disguises herself as a doctor to get close to Arthur, who is kept under Secret Service protection as he inadvertently spills some top secret information about a project called Samaritan. Flashbacks to Harold's teenage life are shown, where the initial idea for creating the Machine emerges in response to his father's memory loss. Arthur's wife, Diane (Camryn Manheim) tells Shaw that Arthur works for the NSA, and Collier's group Vigilance tries to abduct him. Shaw, Harold, Arthur and his wife escape to a hotel, where Harold talks to Arthur to get more information about Samaritan. Arthur describes his involvement in the creation of an AI like the Machine, but mentions that the project was shutdown. Fusco finds Reese in Colorado, where he tries to persuade Reese to come home before they fight outside a bar. As Arthur talks with Finch, he remembers that he buried his wife two years earlier, and the lady pretending to be Arthur's wife Diane reveals herself as Control. Her agents, led by Hersh, barge into the room and capture Shaw, Arthur, and Harold. Control threatens to kill either Arthur or Harold—whoever does not give up the location of his respective Machine. The episode ends with the Machine analyzing threats to its assets and itself, along with Arthur's machine, Samaritan, having its status changed from "Deactivated" to "Unknown".

This continues from the previous episode where Harold, Shaw and Arthur are held captive by Control for information. Shaw is deemed to be not useful and is about to be killed, when Root comes guns blazing and gets them out of there. But Root is shot and captured by Control. Meanwhile it is revealed that Arthur had made a copy of Samaritan before it was destroyed. He stored it in a bank locker. But as they go to get it, Vigilance comes and Harold locks himself, Arthur and the bank manager in the vault. Shaw gets a bomb ready to get everyone out. Inside the vault Harold reveals to Arthur that The Machine exists and convinces him to destroy Samaritan so that it will not fall into wrong hands. Vigilance breaks through the vault and captures everyone including Shaw, but they are saved by Reese and Lionel. The Machine guides Root to escape from Control after having been tortured. She is later shown in a South East Asian restaurant. Root also calls Harold to tell him that the Samaritan drives are not destroyed because the bank manager had been murdered and replaced, and the impostor had swapped the drives. Later, the impostor is shown handing over the drives to Greer from Decima Technologies, who in turn shoots her through the heart to cover his tracks. The episode ends with Greer saying that he has great plans for Samaritan.

The team's next case is that of Kelli Lin (Elaine Tan), a former silver medal-winning Olympic gymnast who is later revealed to be an antiquities thief long pursued by Interpol. Following a robbery at a museum exhibition, Shaw investigates Kelli's house and learns that her next operation is to steal a Gutenberg Bible that is being shipped out that night. Shaw is able to foil the plan but is confronted by Kelli, whose boss Cyril (Gene Farber) is an extortionist revealed to be forcing Kelli to commit robberies while her daughter is kept kidnapped. The team learns that the Bible is being kept in a heavily guarded building belonging to a company called Symmetric Security. Fusco obtains the fingerprints of a guard there while Finch uses a 3D printer to create a fake hand with the guard's fingerprints. That night at the Symmetric Security headquarters, Reese distracts the guards by setting off the alarms in the building, allowing Shaw and Kelli to use the fingerprints to access the room containing the Bible. Kelli uses her gymnastics skills to bypass the proximity detectors and steal the Bible. Finch takes Interpol agent Alain Bouchard (Henri Lubatti), the man in charge of the investigation against Kelli, and they listen in on Kelli's conversation with Cyril so Bouchard can learn the truth. Cyril refuses to free Kelli's daughter, but when he accesses the surveillance feed on her, he sees Reese take down the thugs guarding the girl. Shaw shoots Cyril in the leg before he can kill Kelli and both Kelli and Cyril are apprehended. In an interrogation room at the NYPD, Bouchard tells Kelli that her life before being a criminal was a shame and that she deserved the gold medal. He places a key on a desk, allowing her to leave. The next day, Kelli and her daughter happily reunite after Reese's rescue. That night, the team celebrates their victory and Reese honors Carter by pouring a glass for their "missing member".

In 2010, Harold was working with a man called Dillinger (Neil Jackson), an ex-Blackwater mercenary who performed the same duties currently performed by Reese. Their current number is Daniel Casey (Joseph Mazzello), a hacker who tests computer security systems. They soon find out that multiple parties are attempting to eliminate Casey, including Reese and Stanton (secretly arranged by Control). Dillinger saves Casey and brings him to Harold, who realizes Casey's last job was to find a way to access the Machine. Although Casey failed, he learned enough to warrant Control and Special Counsel to want him dead and his laptop destroyed. Dillinger turns on Finch and steals the laptop from him to sell on the black market. The sale is busted by another agent of Special Counsel (revealed to be Shaw) who kills Dillinger, but fails to stop one of the buyers from escaping with the laptop. Casey is captured by Reese, who decides to let him live against his orders, providing him with safe passage to Canada. Control traces the laptop to China, and orders that Reese and Stanton are sent after the laptop and destroyed along with it. In the present day, Root finds Casey in Alaska and tells him to go to Cartagena, Colombia and seek out Jason Greenfield, her number from "Mors Praematura".

The team receives the number of Maria Martinez (Nazneen Contractor), an engineer working for the international energy company HydralCorp. They follow her and learn that she is working to clear the name of Omar Risha (Haaz Sleiman), a man from Iraq suspected of being a terrorist. Shaw, Fusco and Reese save Maria from an assassination attempt and learn from her that Omar was her translator in Iraq and saved her from a terrorist ambush during the shipment of six generators; the generators went missing and Omar learned about their disappearance, being targeted for it. Finch meets with Omar and learns that the generators were shipped elsewhere and that HydralCorp's corrupt CEO Ken Davis (Casey Biggs) is responsible. Maria and Shaw, meanwhile, discover that Davis has created a false report of Omar's terrorist accusations, and that French United Nations diplomat Rene Lapointe (Michel Gill) has the papers approving Omar's asylum in the US in his office. Maria escapes from Shaw and goes to get them, putting herself in danger. Finch sends Reese, Fusco and Omar (who Reese rescued from deportation) to break into the UN building and save Maria. They stop Greek diplomat Christos Sevon (William Abadie) from killing Maria and reunite with Omar. The episode periodically shows Root's new mission of following Decima head Greer; she takes Bear with her to spy on him, where it is revealed that Davis had the generators shipped to the US so Greer can power Samaritan; Greer has Davis killed and leaves, and Root follows him, using Bear's sense of smell to evade Greer's counter-surveillance tactics. Greer waits for her at an empty subway corridor and talks with her about his motives, offering her a position on his team. Greer's men appear and point their guns at her. Greer calls the meeting a draw and leaves, allowing her to do so as well.

Collier continues the trial. Flashbacks show he was recruited by Vigilance. Reese and Hersh search for the trial venue. Root and Shaw smuggle servers into the Samaritan array. Fusco deals with a diversion. The presidential assistant is put on the stand and becomes defiant; Collier kills him. The Senator refuses to name his superior, but inadvertently reveals that he reports to Control; he is spared. Control refuses to confirm or deny anything. Collier is about to kill her when Finch confesses he is the author of The Machine. With a Vigilance command post now compromised, Collier takes Finch, Greer, Control and the senator to a nearby rooftop. Collier is wounded in a gunfight. Greer tells Collier that he and his Decima team created Vigilance as a "devil" for Samaritan to justify itself, and that he himself recruited Collier. Meanwhile, Hersh has been wounded in a gunfight in the trial building. He finds a booby-trapped bomb but cannot disengage it before it explodes, killing him, several police officers and anyone left inside the building. Greer's lieutenant kills Collier, and is about to kill Finch when Reese arrives and wounds the gunman. In this gunfight, Harold gets a shoulder wound but takes cover. Greer and his gunman flee. Finch and Reese leave once the carnage is over. The principals regroup, but Samaritan is being brought online. Root advises the team to abandon their library home and assume new identities. The code in the servers she and Shaw installed will report the team dead and hide information about their new identities. As Shaw, Root, Reese and Finch head off in different directions and the remaining Vigilance team members are killed on the streets, the now fully operational Samaritan asks Greer for commands. Greer instead asks Samaritan what commands it has for his team. The episode ends with the Samaritan screen displaying, "Calculating response."