Reese and Finch are given the number of a teenager killed two years ago, making Reese question the sources fallibility.

Mr. Reese goes undercover as a chauffeur to get closer to the latest number.

Finch and Mr. Reese are going after a person who seems to be leading a double life. However, they soon realize there are 2 people with the same social security number; one of whom is in danger and one who's an impostor.

Finch and Mr. Reese are tailing a spy working for the NSA. As he gets too close to finding out about the Machine, the Government are out to get him.

Finch and Mr. Reese try to protect a taxi driver that is being chased by the Estonian mafia. HR try to make a deal with Elias.

After saving Leon Tao yet again, Reese goes to Atlantic City to watch over a retiree who's losing a fortune in the casino. HR smears Szymanski so that he can't testify at a Russian mob trial and Carter risks her life trying to clear him.

Finch goes undercover at a tech company to watch a rising VP. The company appears to be riddled with agents who are a front for something more sinister. Shaw reappears and takes an interest in Root. HR decides to rub out an informant.

They wait ten days for a new number due to a system virus, suspecting Root is the problem. It's for Ernest Thornhill, who isn't who, or what, he is supposed to be. At stake is The Machine - will it remain with Finch or end up with Decima?

Reese and Finch team up with surprising allies in a race to save The Machine from Root and the mysterious international organization, Decima, who have both re-emerged with dangerous agendas.

It's Fleet Week in New York City, making the hunt for one Naval Officer among a sea of sailors even more difficult for Reese, Finch and Shaw.

The next number the machine dispenses is for Vanessa Watkins, a hard-nosed prosecuting attorney who, when Finch and Reese first meet her, has just reported her husband, Jeremy Watkins, missing from their yacht. While Vanessa has put away many a criminal over her storied career, Jeremy has let many go as a flashy and high-priced defense attorney. As her number came in after the report of him missing, they know Jeremy's presumed death is not the reason for the number, yet they don't know if Vanessa is the target or the perpetrator. They learn that the lead investigator on the case of Jeremy's death, Detective Cameron, is looking at her for her husband's murder as all evidence found thus far implicates her. Cameron's main problem?: he doesn't have a body, and thus needs Vanessa to confess to make a conviction stick, which she may or may not know. They will also learn that Cameron has a personal vendetta against her, which places a major obstacle in tracking her as she tries to elude Cameron. As Finch and the team wade through the story of the complicated lives of Jeremy and Vanessa - including their unlikely personal coupling - they find that Vanessa knows her law and is resourceful and strategic in her every surprising move. They may not learn if she is the target or the perpetrator without getting the story directly from her. Even then, as she is a lawyer who knows how to spin, they have to act the judge and jury in their own court of opinion in evaluating her story. Meanwhile, as Carter assists them on this case, she finds that she has to be careful around her new rookie partner, Laskey. She doesn't yet know how careful she truly has to be.

Shaw is tasked with staying close to a 10-year-old girl identified by The Machine. Meanwhile, Carter's continues her mission to take down HR.

A hypnotherapist, who's really a con man, pumps his patients for personal information while they are hypnotized. One of his patients is an antique dealer who launders money for HR.

Reese tries to honor Carter's memory by solving a cold case she was unable to.