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.moreless
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.moreless
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.moreless
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.moreless
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.
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.moreless
Sameen escapes her captors and reunites with her teammates, but they soon realize that their friend may not be as free as she believes.
Mickey knows he's a dead man if he gives in to Detective Muncie's demands. Ray comes up with a plan to help him, involving Lee Drexler and an Armenian popstar - but not without some demands of his own. When Bridget gets into a fight at school, Abby investigates her recent strange behavior.moreless
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.
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.
The team must go on a seeming suicide run to prevent the financial meldown that Samaritan has engineered.
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.moreless
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.moreless
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.moreless
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.moreless
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.moreless
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.
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.
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.moreless
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.moreless
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.moreless
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.moreless
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.moreless
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.
A Congressman holds the key to stop Decima from activating Samaritan, and Reese poses as a Secret Service agent to get close to him.
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.moreless
The team receive the Number of a UN diplomat being stalked by a former government contractor. Meanwhile, Root faces an enemy from the past.
Root intersects with the team again when the Machine gives Finch the Number of a janitor after it sends Root to investigate the man.