The FBI close in on Reese, who is trying to protect a psychologist from one of her patients. Meanwhile, Finch receives a visit from an old friend.
Finch gives Reese his birthday off so that his partner doesn't have to face a Number reminiscent of a case from Reese's past.
Reese and Finch learn that their new Numbers are the five Dons of New York City, and figure that Elias is making his move for complete control of organized crime.
Reese and the Machine join forces to track down Finch, who has been abducted by the mysterious Root.
While Carter closes in on Reese and Finch and the CIA close in on her, the two men investigate a suspicious building super whose number has come up.
Reese and Finch must help their new Number, a counter-terrorist operative who is on the run from her own people.
The Machine gives Reese and Finch the number of a down-and-out man who has been pushed too far, and they're forced to turn to former Person of Interest Zoe Morgan for help.
While Carter tries to determine if her boyfriend is working with HR or not, Finch infiltrates a tech corporation to determine if their new Number is trying to help the company or hurt it.
In Texas, Reese and Carter investigate the disappearance of a 14-year-old girl from over a decade ago that may lead them to Finch and his abductor.
Finch finds a lot of in common with their newest Number, who has run afoul of the government. Meanwhile, Reese learns about Finch's past.
Reese and Finch must protect Judge Samuel Gates, who wants nothing to do with their extralegal activities even though his refusal could cost him his life.
While Carter tries to maintain her cover as an FBI temporary agent while helping Reese, Fusco has to protect a new Number on his own while Reese ducks some old enemies from the past.
The Machine becomes increasingly erratic because of the computer virus, and Reese and Finch must find an elusive tech millionaire. Meawhile, Carter puts herself at risk when she tries to find Cal's killer.
Reese and Finch become day-care providers when the Machine gives them the number of a six-month-old baby. Meanwhile, Carter begins to question her alliance with the two men when Elias shows up.
Reese must protect an investigative journalist without letting her know that he's around, for fear of blowing his and Finch's cover.
Reese and Finch go into overtime when the Machine gives them the numbers of four Persons of Interest. Meanwhile, Carter deals with the aftermath of the recent assassination attempt on her, and Reese's past resurfaces.
Reese infiltrates a smuggling ring so that he can protect his newest Person of Interest.
Reese, Finch, and Fusco must protect Detective Carter without giving away their true identities, when the Machine gives them her name as the next Person of Interest.
When Carter meets with Reese for the first time, he asks her to help him with their newest Number: a young lawyer from the wrong side of the tracks whose life is threatened.
Reese goes undercover as an armored car company employee, and faces memories from his past with the CIA.
Reese and Finch help a schoolteacher targeted by the mob after he witnesses a hit.
Reese works as a driver for the newest Person of Interest: an attractive woman who is a master of shady deals. Meanwhile, Carter investigates a murder connected to the stolen evidence box for the M. Elias case.
The team's newest Person of Interest is a teen genius and Finch goes undercover as a substitute teacher to protect him. Meanwhile, Carter takes on her first assignment as a temp agent for the FBI.
To combat Root and Decima, Reese and Finch must seek out unusual allies to save The Machine. Meanwhile, HR prepares to eliminate Carter when she probes into Cal's death. And in the past, the final fate of Nathan is revealed.
Reese and Finch head off to a small coastal town when The Machine gives them the Numbers of six missing people. When a storm moves in, they are trapped at a police station with several locals... and one of them is a killer.
Reese and Finch attempt to protect Mira, a hotel maid with a long list of enemies. Meanwhile, Carter gets a job offer due to her help in the "man in the suit" case.
Reese and Finch discover that their newest Number has almost no digital footprint... and a double life.
Reese and Finch try to help a billionaire tech magnate only to discover that doing so may compromise their existence when he sets out to find out who they really are and what they know.
The newest Number is a famous cardiologist, but by the time Reese gets to the man, it's too late: he's already been given a slow-acting irreversible poison. While Reese and the doctor try to track down the man who poisoned him, Carter has a tough decision to make when IAB moves in on Fusco for the murder of his partner a year ago.moreless
While Carter deals with corruption within her own department, Reese and Finch help an elderly gambler and try to figure out why the mob wants him dead.
Reese's former partner Kara abducts him as part of her scheme to unleash a wave of cyber-terrorism across the world and get revenge on the people she believes wronged her.
A mysterious millionaire, Finch, approaches John Reese, a CIA field officer who is believed dead, and offers him the chance to stop violent crimes before they happen. Finch can predict the person involved, but not how or where they are involved. In his first assignment, Reese must help a district attorney who Finch has predicted will be involved in a violent crime.moreless
Reese and Finch must decide whether to help a mob triggerman who is their newest Number, or leave him to his well-deserved fate.
Reese is off to the suburbs to take on an undercover assignment to protect the newest Number.
The Machine gives the team a new Number: Simmons, the corrupt HR officer that murdered one of their own. Meanwhile, Finch tries to stop a friend from going too far in their quest for vengeance.
The Machine gives Finch Reese's Number as HR puts out a contract on the "Man in the Suit."
While Reese and Finch look after their newest Person of Interest, a teenager whose brother was recently murdered, Finch worries that his dead partner's son Will is getting too close to learning the truth about the Machine.
The new Person of Interest is a young trader who has become involved in a multi-million dollar financial scam, and Reese has to pose as a wealthy investor to watch their client.
As the FBI renews their hunt for Reese, he and Finch try to help a sister of a dead soldier seeking justice for wronged veterans.
To get close to a playboy who stalks and--in one case--apparently kills women, Reese and Finch bring in Carter, Zoe, and Sam to get close to him.
The team's new Number is their youngest: a 10-year-old girl who may be a spy. Meanwhile, Carter continues her hunt for HR.
The team has to protect two Persons of Interest when the Machine gives them the numbers of a husband and wife.
The Machine gives Finch and Reese the Number of a hypnotherapist who is using his craft for personal gain. Meanwhile, Carter gets a lead on an antiquities dealer who could give her the means to bring down HR.
The team must go on a seeming suicide run to prevent the financial meldown that Samaritan has engineered.
Reese and Finch must track a cab driver whose Number has come up... but they don't know if he's involved or if one of his passengers may be the intended victim or predator. Meanwhile, Simmons continues to put pressure on Fusco.
When the Machine turns up a deceased individual as a Number, Finch must remember how he came to create the Machine and determine how the apparent error could have occurred.
Reese and Finch set out to protect a surgeon who has come up as their newest Person of Interest. However, when they discover that someone from Reese's past is involved, they turn to a former Number for help.
The Machine gives the team 38 Numbers, and they realize that someone is pitting HR against their Russian Mob allies with the intention to set off a war. Meanwhile, Carter's past with her ex-husband is revealed.
In 2010, Finch and his current partner help a computer programmer on the run from CIA assassins named Reese and Kara, while a secret group tries to get the programmer's laptop for themselves.
Reese and Finch must hunt down their newest Person of Interest, a man with Cold War espionage who disappeared over two decades ago and has returned to the U.S. for some unfinished business.
A Congressman holds the key to stop Decima from activating Samaritan, and Reese poses as a Secret Service agent to get close to him.
While Reese tries to protect the newest Number, an Internet entrepreneur with a stalker, Finch sends Carter, Fusco, and Sam to find the stalker. Meanwhile, Carter learns to live with her new partner now that she's been demoted to street cop.
Now that they have Samaritan up, Decima begins the hunt for Reese, Sam, and Finch... and plans to use Grace Hendricks to lure Finch out of hiding.
Finch and Sam try to save Arthur Claypool from Control without Reese's help, since he is still MIA along with Fusco.
When Decima prepares to bring the Samaritan AI online, the team finds itself caught between that organizations attempts to wipe them out and Vigilance's plan to put an end to intrusive government surveillance.
While Reese and Finch deal with a new Number, Root abducts Sam to force her to help on a mission for The Machine.
The team's new Number is a mild-mannered insurance agent who is pretending to be a police detective to investigate the supposed suicide of a co-worker's brother. Meanwhile, Finch is sent to a conference in Hong Kong and meets an attractive businesswoman specializing in computers.
The team faces an unusual task when they must save the life of a new Number... who is already dying. Meanwhile, Reese leaves the team and Finch considers his past.
While Finch, Sam, and Root try to protect a pollster who suspects that Samaritan rigged the elections, Reese is sidelined in therapy due to his high number of shootings during homicide cases.
Reese and Finch receive a new Number: Elias, who Dominic wants dead. Meanwhile, Root rescues Sam from Martine but Sam doesn't want to be rescued, and threatens to go public if they don't let her help save Elias.
Reese involves Finch in his attempt to protect a new Number, a mathematics student who is playing a city-wide game. However, they soon discover that the game is much more than a simple scavenger hunt.
The Machine gives the team the Number of a 911 operator, and Finch goes undercover as a fellow operator to help her.
Root intersects with the team again when the Machine gives Finch the Number of a janitor after it sends Root to investigate the man.
The Machine sends the team five Numbers to try and determine what is going on in an impending catastrophe that it is blocked from seeing. Meanwhile, Root brings her assembled team of hackers to New York for the next part of her mistress' plan.
The team receive the Number of a UN diplomat being stalked by a former government contractor. Meanwhile, Root faces an enemy from the past.
To demonstrate its power to the Machine, Samaritan launches a massive effort to shut down all crime in NYC for 24 hours... and then unleash it worse than ever. Meanwhile, Finch and Reese try to keep up with the new influx of Numbers, and Root meets with her opposite number.
While Reese and Root look for Sam in an upstate New York town, Fusco helps out the newest Number with the help of a previous one.
As Finch and Root go on a seemingly random series of errands to save the Machine against Samaritan's onslaught, Dominic threatens to shoot Harper and Elias unless Reese puts him in contact with Finch.
While Reese and his new partner Sam try to find a Number, a naval petty officer in town for Fleet Week, Carter tries to eliminate HR for good after being demoted to patrol officer because of a frame-up. Meanwhile, Root settles in to her new life at the asylum.
The team's new number is a professional wingman, and Fusco has to go undercover as a needy client while Reese deals with a demanding police captain. Meanwhile, Root takes Finch on a scavenger hunt for the Machine.
The Brotherhood goes after two children who stole drug money from them, and Reese has to team up with a DEA agent to stop them. Meanwhile, Finch turns to Elias for help.
After several months of silence, the Machine sends a new Number to Reese and Sam... and Finch, who ignores the call. Meanwhile, Fusco gets a new partner and Elias receives an unexpected visitor.
Samaritan begins to withhold information from the ISA, raising Control's suspicions. Meanwhile, Root and Reese search for their missing teammate.
The team's new Number turns out to be an international jewel thief, and Sam has to get close to the man to find out if he's victim or perpetrator. Meanwhile, Finch recruits Root to help him undermine Samaritan's plans to distribute tablets to school children.
The team's new number is a police academy recruit: a loose cannon who is apparently working for the gangs. Meanwhile, Samaritan sends Martine to track down the woman who prevented it from obtaining the virus.
While Reese and Fusco deal with a backlog of Numbers, the Machine starts giving out false Numbers after its recent reboot. Worse, it flags three of the team members as threats due to their violent histories, and locks Finch and Root out of the system.
The Machine sends the team two new Numbers: Elias and Dominic. Meanwhile, Finch and Root get a clue to Sam's whereabouts, and Control tries to learn the truth about Samaritan.
Reese sets himself to solve a case that Carter was never able to close.
Reese returns to field work and must protect the spoiled daughter of a Brazilian diplomat.
Reese reunites with the team to save an antiquities thief, but the group ends up in a high-stakes heist.
A New York lawyer is suspected in the death of her husband. When her Number comes up, the team must determine if she's the killer or being framed by the real murderer. Meanwhile, Carter has problems with her new partner when he sees her with Reese.
The team's new Number is Frankie Wells, a bounty hunter who refuses to give up on a target despite the threat to her life. Meanwhile, Finch links back up with Beth Bridges.
Reese and Finch try to get the case containing the Machine's damaged code to the station so that they can decompress it. Meanwhile, Fusco deals with the aftermath of Dominic and Elias' shootings, while Root tries to dodge Decima's agents without the Machine's help.
Reese and Finch try to protect a software CEO whose behavior becomes erratic after a hacker attack reveals his secrets.
Finch suspects that a fellow juror is trying to rig the proceedings in a murder trial. Meanwhile, Reese begins to open up to the department's therapist.
Reese and Finch protect a street-savvy grifter who makes the mistake of stealing laundered money from Dominic. Meanwhile, Root infiltrates a software app company on the Machine's behalf.
Vigilance launches a new attack and the team splits up: Finch and Fusco go to Washington to investigate, while Reese and Sam go to a high school reunion to protect their newest Number.
The team's new Number is a psychologist whose unorthodox technique for helping his patients find closure puts him at risk. Meanwhile, in the past Finch tries to deal with the trauma of losing his best friend Nathan.
The team's newest Number has ties to the CIA, endangering Reese's cover when he's forced to intervene.
Reese and Fusco help a transcriber at a software firm who is the team's new Number, while Claire contacts Finch and asks him for help against Decima.
Sameen escapes her captors and reunites with her teammates, but they soon realize that their friend may not be as free as she believes.
Reese and Finch are trapped in a hospital ER when a superflu breaks out... and they realize that Samaritan is responsible. Meanwhile, Fusco continues his own investigation, while Sameen stages another escape.
After Finch goes to the wrong place at the wrong time, Samaritan gets a fix on him and won't stop until it captures him. The team rallies to protect their friend... but not everyone will come out alive.
Reese's efforts to leave New York City and The Machine behind are thwarted when The Machine manipulates his travel plans and seats him on a plane next to a new Number.
Samaritan is connected to the newest Number: a sound analyst who is looking into the death of a high school classmate. Meanwhile, Elias' friend Bruce demands answers concerning who murdered the crime boss.
The team's new assignment is protecting a couple on the day of their wedding. Someone wants to stop the wedding... or do they? Meanwhile, Fusco crosses paths with Bruce when the two of them investigate the new player in town, each unaware that it's Samaritan.
While Root protects a radio host who has tapped into Samaritan's secret communication system, the Machine instructs her in how to use it to contact Sameen. Meanwhile, Samaritan keeps chipping away at Sameen's resolve, and Fusco realizes that Finch and Reese will never trust him with the truth.
The Voice uses a hapless locksmith to plant a bomb in an investment firm, in the first step of a new plan. Meanwhile, Sameen makes her way to New York and Root finds her.
Samaritan makes one last desperate attempt to preserve itself from Finch's virus, and the team go on what may be a suicide mission to stop it.
Finch breaks into the NSA to plan the virus that will destroy Samaritan... and the Machine. The only ones who can get him out alive are Reese, Sameen, and the Machine, if they can get to him in time. Meanwhile, the Machine shows Finch simulations of what the world would have been like without it.moreless
The President is tapped as the next Person of Interest, and the team finds itself receiving some unexpected help. Meanwhile, Finch goes on a roadtrip with the Machine to begin his final campaign against Samaritan.