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
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.
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 Samaritan's resolve, and Fusco realizes that Finch and Reese will never trust him with the truth.moreless
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
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.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.
The team's newest Number has ties to the CIA, endangering Reese's cover when he's forced to intervene.
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.moreless
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.moreless
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.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.