"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".
In the beginning, John Reese, a former Green Beret and CIA operative, is living as a vagrant in New York City after the death of the woman he loves, and is presumed dead. He is approached by Harold Finch, a reclusive billionaire software genius who is living under an assumed identity. Finch explains that after September 11, 2001, he built a computer system for the government that uses information gleaned from omnipresent surveillance to predict future terrorist attacks. However, Finch discovered that the computer was predicting ordinary crimes as well. The government is not interested in these results, but Finch is determined to stop the predicted crimes. He hires Reese to conduct surveillance and intervene as needed, using his repertoire of skills gained in the military and the CIA. Through a back door built into the system, Finch receives the Social Security number of someone who will be involved in an imminent crime, at which point he contacts Reese. Without knowing what the crime will be, when it will occur, or even if the person they were alerted to is a victim or perpetrator, Reese and Finch must try to stop the crime from occurring.
They are helped by NYPD detectives Lionel Fusco, a corrupt officer whom Reese coerces into helping them, and Joss Carter, who in early episodes investigates Reese for his vigilante activities. Although Reese arranges for Carter and Fusco to be partners in the NYPD early in the series, for the entirety of the show's first season, neither is aware that the other is also working with Finch and Reese. Periodically, the team also enlists the aid of Zoe Morgan, a professional "fixer" who applies her skills to particularly difficult tasks. The series features several subplots. One significant story arc involves "HR", an organization of corrupt NYPD officers who are initially in league with budding mob boss Carl Elias and later with the Russian mafia; in earlier parts of this arc, Fusco is forced to go undercover. Another important storyline revolves around Root, a psychopathic hacker who is determined to gain access to the Machine. During season two, another organization of powerful business figures, Decima Technologies, is revealed to be attempting to gain access to the Machine. Carter vows vengeance against HR after they have her boyfriend, Detective Cal Beecher, murdered. Reese and Finch recruit Sameen Shaw, an ISA assassin on the run after being betrayed by her employers. Shaw learns about the Machine in the season two finale and subsequently becomes a member of Reese and Finch's team. In the third season, Carter delves deeper into her investigation of HR, eventually uncovering its leader, but ends up getting killed. Reese briefly leaves the team in his grief but returns. The team also battles Vigilance, a violent anti-government organization devoted to securing people's privacy.
The Machine is a mass surveillance computer system programmed to monitor and analyze data from surveillance cameras, electronic communications, and audio input throughout the world, built in two unoccupied floors at Ingram's company, IFT. From this data, the Machine accurately predicts violent acts. Under control of the U.S. government, its purpose is to foresee terrorist attacks, allowing the government to forestall terrorist activity. However, the Machine detects future violent acts of all kinds, not just terrorism. Originally unknown to Finch, his partner, Nathan Ingram, created a routine called "Contingency", on the eve of the government handover, to access the non-relevant data. Ingram and Finch are seen accessing this program in the episode "Zero Day". In the episode, Finch is appalled that Ingram has the data sent directly to him and shuts down the routine, reactivating it after Ingram's death. He presumably modified and updated the Contingency routine as well, as the Machine then begins to pass on the "irrelevant" non-terrorism data to him in the form of Social Security numbers, via coded messages over nearby public telephones.
Over the course of each episode, the viewer periodically sees events as a Machine-generated on-screen display of data about a character or characters: identification, activities, records, and more may be displayed. The viewer also sees a Machine-generated perspective as it monitors New York. Commercial flights are outlined by green triangles, red concentric circles indicate no-fly zones around key buildings such as the United States Capitol, and dashed boxes mark individual people. The Machine classifies the people it watches by color-coding the boxes: white for no threat or an irrelevant threat, red for perceived threats to the Machine, red-and-white for individuals predicted to be or currently violent, and yellow for people who know about the Machine, including Finch, Reese, Ingram, and Corwin among others; Root is assigned this box during the first two seasons, but is able to communicate with the Machine and act on its behalf in season three, thus giving her a unique black-and-yellow box designating her as the Machine's "analog interface". The white-boxed "irrelevant threat" targets include the persons of interest that Reese and Finch assist.
As the series progresses, a vast government project emerges. Known as "Northern Lights", it revolves around the development and use of the Machine. It is headed by a mysterious figure known only as "Control", an unnamed official who deploys teams of Intelligence Support Activity (ISA) operatives who are identified by the Machine using a blue box; classified as "assets", they have no knowledge of the Machine, but work within its own parameters. They are used to eliminate perceived terrorist threats on the recommendation of a department known as "Research". "Control" also used the team to eliminate key personnel who are aware of the Machine's existence. In the third season, Control physically makes her first appearance, and the organization Vigilance exposes the government's Northern Lights program to the public, forcing Control to shut it down. The private technology firm Decima Technologies steals Samaritan, a creation of Finch's MIT classmate Arthur Claypool that is similar to the Machine, and plans to use it against the Machine.
During the episode "Prophets" a previous generation of The Machines source code was shown on screen. The source code displayed was that of the Stuxnet worm.
John Reese (Jim Caviezel): a former member of the U.S. Army Special Forces and later a CIAblack operations officer who is presumed dead following a mission in China. Little is known about Reese's background and his name is one of several aliases he uses. He lost his lover, Jessica Arndt, prior to meeting Finch, which appears to have marked him deeply. Reese demonstrates skill in the use of a range of weapons, hand-to-hand combat, and counter-surveillance tactics. He knows very little about Finch and often is rebuffed when he attempts to learn more about him.
Harold Finch (Michael Emerson): a reclusive, security conscious and intensely private billionaire software engineer. His real name is unknown and he has many aliases (most commonly Harold Wren), using various species of birds as the last name. Finch has developed a machine that can isolate the Social Security numbers of people with either premeditated homicidal intent or who will be homicide victims, based on its analysis of surveillance data. Following a traumatic event in his own life that led to the death of his business partner and close friend, Nathan Ingram, he recruits Reese to help him deal with the people the Machine identifies. For the first three seasons, Finch lives and works in an abandoned library and beginning with season four, in an abandoned subway stop. Finch shows the results of severe physical injuries, including the inability to turn his head, a rigid posture, and a limp.
Detective Jocelyn "Joss" Carter (Taraji P. Henson) (seasons 1–3): an NYPD homicide detective and the mother of a teenaged son, Taylor. Carter is a former U.S. Army interrogation officer who passed the bar exam in 2004, but gave up practicing the law to return to police work. Carter first crosses paths with Reese following his encounter with a group of young men on a New York subway, but knew him principally as a mysterious man in a suit. Carter is initially determined to apprehend Reese, but eventually forms an alliance with him and Finch (during which she is unaware of the existence of the Machine).
Detective Lionel Fusco (Kevin Chapman): a corrupt cop Reese blackmails into being a source inside the police department. Finch later arranges for Fusco to be transferred to Carter's precinct so that he works with her. Over time, Fusco becomes increasingly loyal to Finch and Reese, but continues to keep a secret regarding the death of a cop involved with HR. Like Carter, he does not know about the Machine's existence.
Sameen Shaw (Sarah Shahi) (season 2, recurring; season 3–present, main): a government assassin who worked for Special Counsel, unknowingly dealing with the "relevant" numbers from the Machine. She is now an ally of Reese and Finch. She has a self-identified personality disorder, and enjoys shooting the bad guys. She states that she is only helping Finch and Reese because of their dog, Bear.
Root (Amy Acker) (season 1, guest; season 2, recurring; season 3–present, main): a highly intelligent computer hacker and contract killer with a keen interest in both Finch and the Machine. Her real name is Samantha "Sam" Groves. The Machine identifies Root as its "analog interface" and uses her as its agent for missions of unknown purposes, as well as an intermediary between itself and individuals with whom it wishes to communicate.
Bear (played by Graubaer's Boker): a Belgian Malinois with military training who Reese rescues from Aryan Nationalists, who were using him as an attack dog. Bear spends most of his time with Finch, who was reluctant to have him in the library at first, but has become attached to him over time. Bear gained his name by eating $1,000,000 in bearer bonds stolen by Leon Tao.
Zoe Morgan (Paige Turco): a "fixer" who specializes in crisis management. Finch and Reese first met her as a person of interest. Later on in the series, she works with them on cases that require her skills. She has an ill-disguised interest in Reese.
Jessica Arndt (Susan Misner): Reese's deceased lover. After Jessica's relationship with Reese ended, she married another man, but remained in contact with Reese. She is eventually killed by her husband during a domestic dispute.
Nathan Ingram (Brett Cullen): Finch's collaborator on the Machine who died from an attack caused by a van bomb. Ingram acted as the interface between the government and their company while the Machine was under development.
Grace Hendricks (Carrie Preston): Finch's fiancée who believes him to be dead following the van bomb attack that killed Ingram.
Carl Elias (Enrico Colantoni): a nascent crime boss and the illegitimate son of Mafia don Gianni Moretti. Elias is determined to revive the crime families of New York and to eliminate the Russian mob. Elias was arrested following an attempt to kill the heads of the Five Families but continued to run his organisation from jail. HR and the Russian mob removed Elias from prison to execute him, but Carter saved him and helps arrange for a safe hiding place. After Simmons killed Carter, Elias has Scarface kill Simmons.
Scarface (Anthony Marconi) (David Valcin): Elias' principal enforcer. He is easily identifiable by a large scar on his right cheek, thus his nickname.
Leon Tao (Ken Leung): a former financial criminal and three-time person of interest who has assisted in some cases with his forensic accounting skills. He has a penchant for get-rich-schemes which always land him in difficulties with gangsters.
Special Agent Nicholas Donnelly (Brennan Brown): an FBI agent who becomes interested in Reese when his case crosses one of Reese's. He periodically offers Carter the opportunity to work with him as he pursues Reese.
The following characters are tied to a government project related to the development and use of the Machine.
Control (Camryn Manheim): the woman who is the head of the ISA's operation (code-named Northern Lights) regarding the Machine.
Hersh (Boris McGiver): Special Counsel's enforcer, a former member of the ISA.
Special Counsel (Jay O. Sanders): a shadowy figure from the Office of Special Counsel who appears to be coordinating the activity regarding the Machine and sees Reese as a threat.
Senator Ross Garrison (John Doman): a U.S. senator charged with overseeing Northern Lights.
Alicia Corwin (Elizabeth Marvel): a liaison between Ingram and the government while the Machine was being developed and a former member of the National Security Council.
Denton Weeks (Cotter Smith): the official who commissioned the development of the Machine while he was a deputy director at the NSA.
Detective Cal Beecher (Sterling K. Brown): a narcotics detective with whom Carter had begun a relationship. Beecher is Alonzo Quinn's godson, but was unaware of Quinn's activities.
Detective Bill Szymanski (Michael McGlone): a NYPD organised crime unit detective that Carter sometimes works with.
Detective Raymond Terney (Al Sapienza): a police detective with whom Carter works regularly.
Detective Kane (Anthony Mangano): a NYPD homicide detective with whom Carter and Fusco have periodically worked.
The following characters are involved in the HR storyline, in which a group of corrupt police officers work to control organized crime in New York.
Alonzo Quinn (Clarke Peters): the Mayor's Chief of Staff and the head of HR.
Officer Patrick Simmons (Robert John Burke): a uniformed officer who is a right-hand man to Quinn and HR's second-in-command. He handles HR activities on the street level.
Captain Arthur Lynch (Michael Mulheren): a major figure in HR with whom Fusco appeared to be working in season 1.
Captain Womack (John Fiore): the captain in charge of Homicide who is Carter and Fusco's supervisor. He protects members of HR when Carter gets too close.
Officer Mike Laskey (Brian Wiles): a rookie cop affiliated with HR who is installed as Carter's new partner after she is demoted to officer for getting too close to HR. She turns him by threatening to frame him for the death of another dirty cop.
The following characters are part of Reese's backstory relating to his time with the CIA.
Mark Snow (Michael Kelly): a CIA operative who once worked with Reese.
Michael Emerson filming Person of Interest in New York City
The series was officially picked up by CBS on May 13, 2011, and debuted on September 22, 2011. On October 25, 2011, the show received a full season order. It was renewed for a second season on March 14, 2012, by CBS, which premiered on September 27, 2012. CBS renewed Person of Interest for a third season on March 27, 2013, with Sarah Shahi and Amy Acker promoted to series regulars. The series was renewed for a fourth season on March 13, 2014.
According to CBS, Person of Interest received the highest test ratings of any drama pilot in 15 years, what one CBS executive called "crazy broad appeal you don't usually see", prompting CBS to move CSI, which was broadcast on Thursday for over 10 years, to Wednesday, opening up a slot for Person of Interest. The pilot episode won its time slot, drawing 13.2 million viewers.
On Metacritic, season 1 scored a 65 out of 100. Of the pilot, David Wiegand of the San Francisco Chronicle said "Person of Interest separates itself from the gimmick pack, not only because of superbly nuanced characterization and writing but also because of how it engages a post-9/11 sense of paranoia in its viewers." David Hinckley of the New York Daily News gave the pilot four stars out of five, commenting on Caviezel's and Emerson's performances, saying Caviezel "brings the right stuff to this role" and Emerson "is fascinating as Mr. Finch." Mary McNamara of the Los Angeles Times stated that in regard to the pilot, "the notion of preventing crimes rather than solving them is an appealing twist... The surveillance graphics are very cool."
In regards to season 3 of the show, Slant Magazine says that the show "is at its best when sticking to cutting-edge topics" and calls it a "solid action-thriller that intersperses twist-filled standalone episodes into its season-long arcs."The A.V. Club said that the show captures the "national post-post-9/11 mood" and that with the mid-season arc in season 3, "turns conspiracy theory into art".
CBS has said that Person of Interest is, ratings-wise, the fastest-growing drama on broadcast television from the 2011–12 season to the 2012–13 season, using ratings up to December 2.
Person of Interest has been picked up by many networks for broadcast outside the United States. It premiered in Australia on Nine Network on September 25, 2011. The series is simulcast in Canada and premiered on City on September 22, 2011, and moved to CTV in 2013. The series premiered in New Zealand on TV One on January 16, 2012. It premiered in the UK on Channel 5 on August 14, 2012.