Thursday's “Person of Interest” finds Reese in prison being interrogated by Detective Carter who has been assigned to the FBI by Special Agent Donnelly. There are four men in custody; each is a suspect of being the elusive "man in the suit" they have been looking for. He claims to be John Warren, and a carefully laid-out identity has been put in place for him.
Now Donnelly wants Carter to wear an earpiece so that she can be fed his questions when she interrogates the four suspects.
Back in 2007, John was in Prague on a covert mission when he first killed three people. Carter asked him if he ever killed anyone. He said yes that he did in Bosnia when a person with land mines tried to kill him. The flashbacks bring John back to his old partner, Stanton and how both had orders to kill each other.
While in prison, for his one-hour exercise and fresh air, the Arian Nation member he took the dog from was there with an agenda, but someone else wanted to see him; Elias. Elias has affection for John and will not turn him in. However, a guy who was shooting a gun intending to be caught is in there too. Reese wants Elias to get a picture of him and find out who he really is. The man is sent by Pennsylvania Two to kill all four of the "man in the suit" suspects.
The fire alarm goes off in the prison as they are interrogating McAvoy, the red-haired prisoner of the four. Finch tells Carter to slip her phone in the prisoner's pocket. He hears Finch on the other end tell him that he knows who he really is, and that he drained his bank account in the Cayman Islands and who would he rather deal with; Finch or the FBI. He comes back in and fingers the other suspect; not John. Donnelly comes in order to take his deal off the table, because the man he fingered just hung himself. The man did not kill himself, but the guy from Pennsylvania Two killed him. Donnelly had the prisoners start a riot and beat up John to see if he would fight back using his military skills, he did not use them this time.
Fusco was protecting a blonde who killers were after (John's usual job). Once he protects her and wards off the killers, she kisses him out of gratitude. She is beautiful and fans appreciate seeing usually stern Fusco actually have a moment.
John is finally released because the charges cannot stick, and he later meets Carter in a quiet location in a park. Suddenly, Donnelly appears to arrest both for conspiracy. He orders her to cuff Reese, and then he cuffs her.
As Finch is walking down the street, pay-phones continue to ring until he finally answers one. This is the machine telling him that Agent Donnelly is in danger and the next "Person of Interest."
Just as he calls him, the car the three of them are in is t-boned. As Donnelly is awakened from the collision, he sees Stanton, who immediately shoots him dead. She then injects John in the neck with a hypodermic needle as the scene closes.