After the initiation of "The Correction," Root faces a potentially futile fight. Meanwhile, Reese and Finch search for the Machine's source code.
A glitch causes the Machine to identify dozens of people not involved in crimes, and Reese and Finch themselves become targets.
The latest POI turns out to be the brother of a soldier Reese was assigned to kill in his CIA days, who's been investigating the soldier's death.
Shaw escapes after Decima subjects her to extreme mental torture, only to realize her mind-bending torment has just begun.
Reese protects an NYPD analyst circling a deadly technological rabbit hole. Fusco investigates the matter enough to become a Samaritan target.
The Machine points the team to a seemingly open-and-shut case involving a wedding, but the crime proves to be more complex than expected.
Root finds herself drawn to a conspiracy-theory radio show's station, where she discovers a key to Samaritan's covert operations.
Reese and Finch struggle to escape a hospital after Samaritan synthesizes a lethal virus. Shaw plans her own escape from what could be a simulation.
A familiar criminal known as "The Voice" re-emerges, and Reese and Finch find themselves trapped in the precinct, besieged by a vicious gang.
After his number comes up, Finch must face an onslaught of increasingly brutal attacks by Samaritan's agents, putting the entire team in danger.
The team faces a huge challenge when the next number turns out to be the president of the United States. A distraught Finch considers going rogue.
The Machine advises Finch as he struggles with the idea of deploying his virus. Reese and Shaw receive a number that points them toward Finch.
Finch and the team chase down Samaritan as it spreads itself across systems worldwide and beyond, and they quickly realize sacrifices must be made.
A presumed-dead former CIA agent teams up with a mysterious billionaire to prevent violent crimes by using their own brand of vigilante justice.
When they are given the Social Security number of a teenager who was killed two years ago, Reese and Finch question the infallibility of the Machine.
When the Machine directs Reese and Finch to a former soldier with shady connections to a crime ring, Reese must infiltrate the gang.
When the number comes up on a promising young doctor, Megan Tillman, Reese and Finch must unravel the threat while she's on-call and after hours.
When the Machine produces the number of a judge, Reese and Finch must investigate a POI who wants nothing to do with their brand of vigilante justice.
Reese finds himself captivated by their latest person of interest, a beautiful, shrewd and remarkably resourceful woman adept at problem solving.
The Machine identifies a schoolteacher who witnessed a mob hit as Reese and Finch's next person of interest.
When their latest POI has connections to Cold War espionage circles, Reese and Finch learn how covert ops were handled in a world before the Machine.
Reese and Finch's game of cat-and-mouse with Carter becomes infinitely more complicated when the Machine declares that she is their latest POI.
As Detective Carter deals with the fallout from her recent encounter with Reese and Finch, the Machine gives the duo four numbers instead of one.
Reese works the computer while Finch does the legwork with their latest target, a building superintendent who keeps too close an eye on his tenants.
Carter finally comes face-to-face with Reese, and now that she knows what Reese and Finch do, she has to decide once and for all which side she's on.
Reese and Finch's latest POI is a luckless man who may have reached his breaking point. As the case evolves, the duo calls upon a former POI for help.
The Machine identifies a vengeance-minded teenager whose brother was just murdered as the next POI.
Reese infiltrates a smuggling ring to get close to his latest person of interest ... who may be hiding a secret identity.
The Machine leads Reese and Finch to Wall Street when a trader at a major investment bank becomes embroiled in a multimillion-dollar financial scam.
When the Machine spits out the number of a 6-month-old baby, Reese and Finch turn into overly protective parents, with an arsenal at their disposal.
The Machine's latest number presents a challenge since the person has virtually no digital footprint and appears to be leading a double life.
When the Machine spits out the numbers of the don's of five crime families, Reese and Finch suspect Elias is planning to eliminate his competition.
The Machine's latest number places Reese undercover with an armored truck crew, a case that brings back memories of his last CIA mission.
It's Reese's birthday, and Finch gives him a day off when he realizes that the Machine's latest number is certain to revive painful memories.
The newest POI's curiosity could spell his doom when he finds himself embroiled in a government conspiracy, one that Finch is all too familiar with.
When a psychologist's number comes up, Reese must protect her from one of her patients while eluding capture by the FBI, who are closing in fast.
The Machine resumes giving Finch its "irrelevant" numbers for people in danger, which include a U.S. naval officer in town for Fleet Week.
When the number comes up for an Internet data broker in the business of eliminating people's privacy, he finds his own being rapidly stripped away.
Carter, Shaw and Zoe Morgan use their feminine wiles to bait a chameleon playboy who is either a predator or someone else's imminent prey.
When the Machine issues the number of a prominent lawyer whose husband was recently murdered, the team must determine if she orchestrated the death.
When Shaw is tasked to stay close to a 10-year-old identified by the Machine, she grudgingly develops respect for the girl's skills in surveillance.
Freed from her psych ward confinement, Root receives a directive from the Machine that requires Shaw's assistance -- by any means necessary.
When the Machine issues the number of a hypnotherapist, the POI team discovers that he is more than just a master of the mind.
The POI team's war with HR nears a boiling point when Finch receives 38 numbers at once from the Machine.
Danger closes in when the battle to bring the criminal organization HR to justice reaches new heights, and the team faces their greatest threat yet.
As the POI team seeks justice for one of its own, Finch realizes one of his team members may go one step too far in order to end the war with HR.
Flashbacks to Finch's adolescence provide insight into his creation of the Machine, and the team receives the number of a dying man.
Enemies converge on the POI team as they protect a dying man whose number has come up, and being down one man could have catastrophic repercussions.
Boarding an international flight in an attempt to put the past behind him, Reese is angered when he realizes the Machine has other plans for him.
Reese rejoins Finch in New York, but a daring plan could make his first new mission the team's last as they pull the number of a highly skilled thief.
Finch goes undercover in an emergency call center to protect a 911 operator but soon realizes the threat reaches further than the team anticipated.
The secrets of Finch's operation before he enlisted Reese are revealed, including shocking ties to present day events.
The Machine assigns Root to seek out a janitor with a mysterious past, but when her very presence puts his life in danger, Finch also gets his number.
Finch and Reese are given the number of a former government contractor who is stalking a diplomat; an enemy attempts to gain an upper hand on Root.
Reese and Shaw infiltrate their most dangerous location yet: a high school reunion, posing as alumni in order to keep eyes on the latest POI.
Reese poses as a Secret Service agent to get close to a congressman who may hold the key to derailing Decima's plans to bring a second Machine online.
As Decima uses Samaritan's feeds to hunt Reese and Shaw, Greer exploits Finch's greatest weakness by threatening his former fiance?e, Grace Hendricks.
An unknown entity prevents the Machine from seeing the full picture of an impending catastrophic event; Root's team of hackers arrives in New York.
The team takes desperate actions in its race to prevent the malevolent AI program Samaritan from coming online and making them its first targets.
As the team struggles to adapt to their new lives, the Machine leads Reese to a man who has developed a communications network invisible to Samaritan.
A reluctant Finch agrees to help Reese protect a gifted college student who is caught up in a dangerous cryptographic game.
Fusco goes undercover to keep tabs on a professional "wingman" and gets tangled up with the mob, while Root and Finch embark on a mysterious mission.
A pair of young siblings and a drug deal gone awry bring the team closer to a gang known as "The Brotherhood."
Finch smells a rat when a talented political pollster's number comes up just as his election predictions go drastically wrong.
An office worker playing detective stumbles into a high-stakes conspiracy, while Finch meets an intriguing woman in Hong Kong.
Shaw joins forces with an international thief whose number has come up, but their heist takes an unexpected turn.
A young recruit's strange behavior leads Reese to a traitor on the police force, while Samaritan gets closer to identifying one of the team.
Shaw goes underground after her cover is blown, while Reese and Finch are caught in an explosive gang war between Elias and the Brotherhood.
In a bid to lure the Machine out of hiding, Samaritan brings all crime to a halt in New York City -- leaving the team with a tricky choice.
As the team rushes to stabilize the stock market after a cyber attack by Samaritan, the Machine must choose between several risky scenarios.
A showdown over a suspected terrorist strains the government's ties with Samaritan and leaves Control questioning the program's motives.
The search for Shaw leads Root and Reese to a quaint upstate New York town where things are not quite as they seem.
Finch suspects a fellow juror in a murder trial of trying to rig the outcome; Reese grows closer to his counselor.
A software programmer's concerns about a string of suicides make her a target, and a former person of interest reaches out to Finch for help.
A grifter earns powerful enemies when her plot to steal from a medical marijuana dispensary turns deadly.
A psychologist whose wife was murdered hatches an elaborate plan to find closure in a case that stirs up painful memories for Finch.
While Reese tries to protect a stubborn bounty hunter whose life is in danger, Finch moves ahead with the plan he set in motion in Hong Kong.
The team scrambles to save a software developer who was framed in a malicious hack before Samaritan agents can get to him.
Reese tackles a homicide case that Det. Carter was trying to solve before her death, but his discoveries put him in danger.
Reese and Fusco wade into a dangerous turf battle, Finch and Root hope a new clue will help them find Shaw, and Control goes rogue.
Finch and Root desperately try to save the Machine as Samaritan closes in, and Reese is caught up in the final showdown between Elias and Dominic.
Reese and the Machine join forces to track down Finch, who has been abducted by the mysterious Root.
Delivering the number of a cold case, the Machine leads Reese ever closer to catching up with Finch and his kidnapper.
With Finch back in the library, Reese returns to fieldwork, only to face his toughest case yet: protecting the daughter of a Brazilian diplomat.
When their latest POI is a killer whose life in now endangered, Reese and Finch must decide whether to intervene or allow karma to take its course.
Reese must protect an investigative journalist without her knowing it or risk becoming part of her story.
Reese is out of his element when the Machine's latest number sends him to suburbia, forcing him to play house undercover in an idyllic neighborhood.
The Machine gives Finch and Reese the number of a brilliant surgeon, but they soon discover that a third party has raised the stakes for this POI.
The team find themselves spread thin when the numbers come up for both a husband and his wife. Will it be "till death do us part"?
Finch and Reese's surveillance skills are tested when a cabbie's number comes up and any one of his fares could be involved in the impending crime.
Reese's latest person of interest becomes a personal quest after he learns that she's the sister of a soldier who was killed in action.
Finch goes undercover as a high school substitute teacher to protect a teenage genius who reminds him of his own adolescence as a child prodigy.
Carter plays a dangerous game by engaging in mental warfare with the FBI to help Reese evade agent Donnelly's narrowing focus.
Caught in the crosshairs of a former acquaintance organizing an act of cyber-terrorism, Reese is abducted. Now, the team must race to save his life.
A tech billionaire POI's curiosity and infinite resources threaten to expose Reese and Finch's identities and sabotage their efforts to save his life.
Reese and Finch race to save the life of a hotel maid but find themselves surrounded by more suspects than they may be able to eliminate.
Lethal and sexy government operative Sameen Shaw finds herself on the run -- and the new focus of Reese and Finch's attention.
Forced to hole up with a group of locals during a storm in a coastal town, Reese and Finch realize there is an unidentified killer hiding among them.
When an elderly card sharp's number comes up, the duo travels to Atlantic City to delve beneath the surface of their POI's seemingly ordinary life.
When the number of a leading tech executive comes up, Finch infiltrates her corporation to gather intelligence.
When a respected surgeon is poisoned, Reese and Finch have 24 hours to determine the deadly toxin he was given and find the person behind the attack.
A virus has rendered the Machine erratic, causing it to issue numbers irregularly. Reese and Finch must race against the viral countdown.
In the second season finale, Reese and Finch team up with some surprising allies in a race to save the Machine from a familiar, nefarious entity.