You are being watched. The government has a secret system, a machine that spies on you every hour of every day. I know because I built it. I designed the machine to detect acts of terror but it sees everything. Violent crimes involving ordinary people, people like you. Crimes the government considered "irrelevant." They wouldn't act, so I decided I would. But I needed a partner, someone with the skills to intervene. Hunted by the authorities, we work in secret. You'll never find us, but victim or perpetrator, if your number's up... we'll find you.Person of Interest is a science fiction action-thriller TV series that started airing in September 2011 on CBS. It was created by Jonathan Nolan and developed along with J. J. Abrams and Bryan Burk. Prior to airing, it was much-hyped for the strong pedigree of cast and crew, and later the pilot received positive reviews. The show has thus far aired four complete seasons, with a fifth and final 13-episode season currently airing, with the series finale scheduled for June 21, 2016.John Reese (Jim Caviezel) is a former CIA agent, reduced to living rough as a drunk homeless man in New York City after a falling-out with the United States government. He's bailed out of trouble with the NYPD by a mysterious billionaire named Mr. Finch (Michael Emerson), who has a strange and potentially-dangerous job offer. As it turns out, Finch is a software genius who designed the government supercomputer—"The Machine"—that monitors all surveillance data, analyzing and filtering for persons involved in potential threats to national security. When The Machine identifies one of these persons, it transmits the individual's Social Security number to the government.As a side effect, The Machine also spits out "irrelevant" numbers that correspond to someone that it predicts will soon be involved in a violent crime which is not relevant to national security. To help these potential victims (or to stop these potential killers, as the case may be), Finch hires Reese and together, they use their collective skills and resources to help innocent people. Along the way, they cross paths with Detective Joss Carter (Taraji P. Henson), who is at first an antagonist, investigating a number of violent incidents involving a mysterious "man in a suit" (Reese), but who later begins cooperating with Reese and Finch.Rounding out the cast of weekly rogues and "irrelevant numbers" is an ensemble of recurring characters, many of whom are important to the longer story arcs:
— Harold Finch, Season 1 Opening Narration
- Detective Lionel Fusco (Kevin Chapman), a former Dirty Cop trying to redeem himself by working with Reese and Finch.
- Zoe Morgan, a "fixer" who trades in favors and information with the city's elite and flirts with Reese.
- Carl Elias, an elusive mob boss and master criminal, ruthless yet also honorable, whose conspiracies and criminal enterprises have generated several POI numbers.
- "HR", a network of corrupt NYPD cops and politicians which, at different times, has both opposed and supported other crime syndicates such as the Russian mob and Elias' organization.
- "Root" A.K.A. Samantha Groves (Amy Acker), a master hacker obsessed with The Machine who becomes its "analog interface."
- Grace Hendricks, Finch's former fiancee, who believes he is dead.
- Northern Lights, the government program that deals with Relevant threats identified by The Machine, and is ruthless in suppressing all knowledge of The Machine. It often acts through personnel from other government agencies, including figures from Reese's time with the CIA.
- Leon Tao, an accountant with a penchant for getting into trouble.
- Bear, a trained military dog.
- Sameen Shaw (Sarah Shahi), a Distaff Counterpart to Reese.
- Decima Technologies, a shadowy private intelligence organization based in China which tries to control The Machine.
- Vigilance, a group of people opposed to the lack of personal privacy caused by government and corporate data mining actions, who became radical enough to start killing the people they considered the most egregious offenders.
- The Brotherhood, a tech-savvy street gang that moves to take over the drug trade in New York.
- "Harper Rose," a skilled grifter.