A woman is driving her car in a parking garage and hits a man. Someone makes a call saying that they have a problem.
Reese sits down with Finch at a diner and asks him what’s good, and the programmer refuses to answer, figuring it’s an attempt to learn more about him. Finch then gives Reese a menu and leaves, and Reese confirms that there is a photo of their next Person of Interest in it. It’s Judge Samuel Gates, who lives with his son Sam Jr. The boy’s mother, Elizabeth, died of cancer a year ago, and Gates hired a nanny, Christina Rojas.
Reese begins watching Gates in court, planting a camera in the fire alarm. He then breaks into Gates’ office and confirms that he has a lot of enemies due to his tough stance on crime, and that he’s received dozens of death threats. Finch identifies six possible suspects for Reese and begins to run down their backgrounds. Meanwhile, Reese continues to watch Gates, and sees two men approaching the judge. He moves in to dispose of them, but one of them receives a call on a throwaway cellphone, tosses it into the garbage, and walks away from Gates with his companion. Reese checks the cell phone and finds a text message saying that Sam Jr. is out of school. He heads for Gates’ apartment just as three men emerge with the boy. Reese takes out two of them, but the third one manages to shoot him in the shoulder and escape with the boy.
When Reese gets back to the library and tends his wound, Finch informs him that the Machine is correct and that the kidnapping plot must somehow end with Gates’ death. When he wonders what they do next, Reese says that his plan is to find Sam and bring him home.
The head kidnapper calls Gate and tells him not to bring in the authorities, and then hangs up. As Gates calls Christina and the school to determine what happened to Sam, Reese approaches him and offers his assistance. At first the judge suspects that Reese is with the kidnappers, but Reese insists that he isn’t and that he was at Gates’ home and tried to stop them. He figures that the kidnappers are keeping Sam alive as a bargaining chip and there’s something they want Gates to do. When Gates wonders who Reese is, Reese tells him to focus on getting his son back.
Reese takes Gates back to the apartment and confirm that Christina is gone. Gates doesn’t believe that she was involved, and Reese confirms that the judge hasn’t handled any cases involving kidnappers. Reese leaves, telling Finch that they’re going to find Sam no matter the risk of exposure, and goes to Christina’s apartment. The nanny is dead, shot dead, and Reese removes a bullet from the wall before calling 911. He figures that the kidnappers tortured Christina for the alarm codes and then disposed of her. Meanwhile, Finch tracks the cell phone used to call Gates, but warns Reese that it will take time to hack the phone company’s firewall.
At the station, Fusco checks Carter’s desk for her files on Reese. She comes in just as he puts the files back, and she wonders why he’s there. Carter has done a background check and learned that there were a lot of crooked cops at Fusco’s old precinct. Fusco dismisses her concerns and then gets a call from Reese. He goes to get coffee and meets Reese at the coffee cart. Reese gives him the bullet from Christina’s apartment and tells him to do a ballistic check, and then asks him what Carter has on him. Fusco warns that she doesn’t have anything yet but she won’t stop until she finds something. When Reese mentions that he’s dealing with a kidnapped boy, Fusco takes an interest only to discover that Reese has slipped away.
Finch hacks the phone company firewall and tracks the cell phone to one Leon Turski. Reese takes the man down at his apartment, tosses him down a flight of stairs, and confirms that the man is with SP-9, an Eastern-European street gang that runs a kidnapping ring.
Detective Olson calls Carter to Christina’s apartment and tells her that witnesses confirm that Reese was there. She doesn’t believe that Reese killed Christina, but wonder why he was there. They send a cop to talk to Gates, who says that his son is fine and he has no idea what happened to Christina. Reese hides behind the door and listens to the entire thing. Once the officer leaves, Reese assures Gates that Sam is still alive and that he needs his help. When Gates wonders if he can save his son, Reese says that he can remain invisible. The SP-9 kidnapper calls and puts Sam on the line to confirm that he’s still alive. He then tells Gates to dismiss the hit-and-run driver, Angela Markham, who is currently before him. She was an account executive who was drinking heavily at a company party and killed a CPA while driving.
Reese tells Gates to stall so he has time to track down SP-9, and then meets with Finch and has him check Angela’s background. Meanwhile, Reese goes to see Turski, who he’s locked in the trunk of his car and left to starve. Turski refuses to give Reese anything on his boss, and Reese locks the trunk back up.
At the precinct house, Fusco chats with Carte as she examines photos of the bullet holes from Christina’s apartment. Reese calls Fusco, who has nothing to report on the ballistics, and the detective insists that Reese needs his help to track down the killer and get a lead on SP-9. Carter thinks that Christina was shot by a jealous lover, but Fusco points out that all the evidence indicates a professional hit. Impressed, Carter invites him to help.
Finch goes to Gates’ courtroom as he tries to stall on Angela’s case. The programmer clones Angela’s phone. Meanwhile, Reese drives his car around, jostling Turski in the trunk, and then asks him again for information. Turski claims that SP-9 works in cells and he only knows the names of the men in his group. He does give Reese the address of the apartment where he gets paid, and Reese shuts the trunk lid and goes to check it out.
When Gates try to stall the case, undermining prosecutor Monica Ramirez’s case, he warns her that she needs to end the case and quickly. When Gates goes to his chambers, the head kidnapper calls and tells him to stop stalling, but Gates insists that he has to make it look legitimate. The kidnapper sends him a cell phone photo of Sam and hangs up. Meanwhile, Finch intercepts a call from the head kidnapper to Angela. He warns her that their operation is in jeopardy because she got drunk, but Angela insists that she’ll finish their deal once she’s cleared of the charges.
Reese goes to Turski’s address and the man who shot him earlier, Drost, spots him. After a brief fight, Reese knocks out Drost and checks the apartment, and discovers that it’s a major SP-9 money-laundering operation. He calls to tell Finch that he knows how they can hurt the kidnappers.
The head kidnapper soon learns that two of his men and $500,000 in laundered money has disappeared. Reese takes the money to the library and Finch updates him. Angela works at a tech company that designs software capable of detecting money-laundering transactions. She oversaw the installation of the software at Onestate Bank, and Finch figures that she deactivated the software to let SP-9 launder millions of dollars safely through the bank. SP-9’s files will include all of the real estate that they purchased, so Finch plans to go there and access the records and figure where they’re keeping Sam.
Reese goes to give Gates the new but the judge insists that he can’t put his son at risk. He reverses his ruling on the admissibility of the primary piece of evidence, the parking garage surveillance footage, and refuses to grant Ramirez a mistrial.
Finch poses as a technician and goes to Onestate to access the SP-9 files. When another technician challenges him, Finch bluffs it out and tells him that he’s there to replace the man since their firewall has been compromised.
Reese puts Drost in the trunk of his car with Turski and tells them to give him the boy’s location. When Drost refuses, Reese unties Turski, tells him to get the information from Drost, and closes the lid again.
At the precinct house, Fusco and Carter are trying to track down the nanny’s killer and Fusco finds security footage of Drost. He confirms that Drost used a car belonging to a company, Coldfield Holdings, in Brooklyn. While Carter prepares to check it out, Fusco texts Reese with the name of the company.
Turski gets Drost to give him the name of their boss, Jarek Koska, and Reese pays him off with a hamburger. Meanwhile, Finch has confirmed that Angela shut down the bank’s anti-laundering software for three minutes each day, letting SP-9 launder their money in safety. He warns Reese that SP-9 has dozens of shell companies, just as Reese receives the text message from Fusco. Once he has the company name, Finch is able to come up with an abandoned church near the Gates household. Reese goes there but discovers that it’s empty. Finch is at the courthouse and watches as the jurors find Angela not guilty.
As the trial ends, Koska calls Gates and tells him to come alone. Finch monitors the exchange and warns Reese, who figures that it’s a trap but that Gates won’t listen to him. As Gates leaves, Reese grabs Angela as she leaves the courthouse. He takes her to the park where Koska and his two men have arranged a meeting with Gates. Gates offers himself for his son but Koska refuses and prepares to kill them both. Reese arrives and tries to trade Angela for the Gates family. When Koska prepares to shoot Reese and his partner, Reese says that his partner has transferred all of his clients’ money to an offshore account. If Koska doesn’t turn Sam over, Reese will wire all of Koska’s clients with the news that he lost their money. Koska tells his men to kill everyone, and Reese takes him and his men out. Once Gates leaves with his son, Reese tells Koska and Angela that he’s taking them for a little ride.
At the courthouse, Ramirez discovers someone has slipped her a folder with a log of Angela’s activities at Onestate. She’s unaware that Finch has left it there, and he quietly slips out of the courtroom.
Fusco and Carter go to arrest Drost at his apartment and find Koska, Angela, and their thugs tied up next to the launder money. Reese watches from the street as the criminals are taken away.
Later, Reese approaches Gates while he plays soccer in the park with his son. Gates thanks him for his help, but warns that he won’t be able to do anything to protect Reese when the authorities catch up to him. Reese tells him to enjoy his time with his son and goes to meet Finch at the diner. He tells Finch that Gates promised to help them if they ever got caught, but Finch points out that he listened in to the conversation. Reese simply says that he read between the lines and then thanks Finch for giving him a job. Finch, touched, tells Reese to try the Eggs Benedict and says that he’s had them plenty of times there.