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."
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 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 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.
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 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.
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.
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.
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.
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.
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.