"Prisoner's Dilemma" is the twelfth episode of the second season of the American crime drama television series Person of Interest. It is the 35th overall episode of the series. It was written by David Slack and directed by Chris Fisher. It originally aired on CBS on January 10, 2013. The name of the episode is based on game theory concept of the same name.
Reese (Jim Caviezel), having been captured by the FBI in "Shadow Box", is detained in Rikers Island along with three other men suspected of being the mysterious criminal dubbed "The Man in the Suit". Carter (Taraji P. Henson) attempts to stall the investigation and is initially forced to play along with the idea that Reese is a criminal, under the watchful eye of agent Nicholas Donnelly (Brennan Brown). Reese remains silent during the first interrogation.
Finch (Michael Emerson) works to help Carter get Reese out of jail, and in the meantime assigns Fusco (Kevin Chapman) to their latest number, supermodel Karolina Kurkova.
The other three suspects being held use cover identities including bank workers. Reese is brought before Carter and goes under the fake name John Warren. Operating from the Library, Finch uses his computer expertise to create IDs and confirmation records for everything Reese says about himself. Reese claims that he doesn't know why he was arrested and simply wants to go home.
In Washington D.C., Special Counsel (Jay O. Sanders) receives a report on the Man in the Suit and asks his man Hersh (Boris McGiver) to track down the operative, informing him that he is being held with three other suspects in Rikers. Hersh decides to eliminate them all and gets himself arrested.
Carter convinces Donnelly to uncuff the suspects in order for them to gain her trust, and keeps Finch informed of the investigation. Donnelly reviews the evidence he has on the suspects' backgrounds and goes to an address where "John Warren" works. It is a complete business including "Warren"'s personal belongings. Finch calls Carter to tell her that John Warren is Reese's most complete cover identity, though work is still to be done and the whole operation could be jeopardized if Donnelly spots even a single flaw. They decide to try pinning one of the other suspects as the Man in the Suit as Finch searches the other suspects' backgrounds for any link to criminal activity. Donnelly later gives Carter an earpiece for his assistance during interrogations.
A flashback to 2007 shows Reese and Kara Stanton (Annie Parisse) in a CIA mission, and Reese's discomfort with being an assassin. Kara reassures him that their victims are not innocent, and that loving a job makes you good at it.
In the present day, Carter asks Reese if he's killed anyone, but Reese asks her the same question - she agrees to answer if he does so first. Reese talks about how he killed an enemy militant in Bosnia, being forced past his discomfort with the subject. He continues on about his family with all of his information matching records quickly being created by Finch. Donnelly is not satisfied with Carter's soft and friendly approach, but insists they get as much information as possible out of the other men. Hersh, meanwhile, is brought into Rikers as Carter interrogates the other suspects. One man's cover is broken and he is identified as Brian Kelly; Donnelly confirms he has no connection to the Man in the Suit.
During food and exercise time, Reese enocunters Byron (Terry Serpico), the former owner of his dog Bear. Before he can attack Reese, Byron is stopped by a hulking man who brings Reese to his old foe Carl Elias (Enrico Colantoni), who offers his help to Reese. Though cautious, Reese points out Hersh and requests that Elias send a photo of him to Finch.
A flashback to 2009 shows Reese and Kara going to a bar and killing a group of terrorists posing as a couple.
During another interrogation, Reese tells Carter about his military service. Donnelly interrupts to inform Carter that another prisoner wants to talk; the man reveals his real name as Charles Macavoy and requests immunity in exchange for everything he knows. Donnelly agrees to the deal if Macavoy can identify the Man in the Suit. Suddenly, the fire alarm goes off, and Finch tells Carter he is responsible. He asks her to sneak her phone into Macavoy's pocket, and calls the prisoner, blackmailing him into following his instructions. The fire alarm is confirmed to be false, and Hersh kills Kelly in his cell.
Macavoy identifies the other remaining suspect as the Man in the Suit, but Donnelly gets a message and realizes that someone got to Macavoy - he tells Carter that Kelly apparently hung himself and observes how Macavoy appears to be too nervous to tell the truth and figures that if he is pointing to one suspect, the other suspect, Reese, must be the man.
Another flashback shows Kara lecturing Reese on being a killer rather than a "boy scout", and them subsequently kissing.
Reese tells Carter in an interrogation of how he was forced to leave his lover for military service. Donnelly later suggests one last test to Carter that will finally reveal Reese - he sends Reese out into the yard and allows the other inmates to beat him in an attempt to see his fighting skills. Reese deliberately allows himself to be beaten until Elias asks the inmates to back off. Carter is furious at how far Donnelly is willing to go and interrogates the other suspect, Packer, and irritates him enough to get him to choke her and pin him as the Man in the Suit instead. Reese is released from prison.
Reese thanks Carter for her help, when Donnelly suddenly comes with a gun, having heard their conversation and realized that Reese is indeed the Man in the Suit. He handcuffs them both, telling Carter she wasted a career helping a criminal.
Flashbacks to 2010 show Mark Snow (Michael Kelly) secretly informing Reese to kill Kara and vice versa, and the subsequent mission in Ordos where Kara is presumably killed by a missile (all from "Matsya Nyaya").
Fusco, meanwhile, saves Kurkova from Armenian mobsters. He calls Finch, who suddenly receives a number from The Machine.
Donnelly talks to Carter while driving, confronting her with evidence that she was helping Reese the whole time. Finch, meanwhile, is horrified to realize that the new number is Donnelly's - he calls to warn him when a truck hits the car. Kara Stanton steps out, shoots Donnelly, and sedates Reese.
The episode gained 15.67 million views in the US.
The episode received near universal acclaim. Tim Surette of TV.com lauded the episode's writing, saying "'Prisoner's Dilemma' was as complete an episode of Person of Interest as there's ever been. When the show is at its best, it's entertaining from several different angles. It's intense, whether the intensity comes from action or interrogations. It's expansive, unraveling the complex story and mysteries behind its central characters. And it's damn funny, surprising its audience with self-aware humor that's disarming. "Prisoner's Dilemma" hit all these marks without wasting a second, creating an episode with a forward momentum that could not be stopped by anything." Sean McKenna of TVFanatic.com also gave a positive review, saying "Really, just when you think you have the show pegged, it throws you for a great turn and coming back for more."