Because it's Reese's birthday and because there are no new numbers, Finch gives Reese the day off. However, there is a new number that Finch believes would not be a good case for Reese to work on, since it may hit a little too close to home regarding the nature of the death of his ex-girlfriend, Jessica Arndt. Reese is aware of Finch's motives. That number belongs to Karen Garner, who Finch is pretty sure is the victim. He is certain that Karen Garner is an assumed name and that she is on the run from someone, probably a violent boyfriend or husband. The case does hit home for Reese who decides to take matters into his own hands much like he would have handled the situation if the woman was Jessica. This situation doesn't sit well with Carter, who has been asked by FBI Agent Donnelly to assist in the investigation on Reese and finding his DNA at a past crime scene in New Rochelle, that crime scene being the death of Jessica's husband, Peter Arndt. Finch encourages Carter to join that investigation knowing what she will find out about Reese. She ends up finding more than Finch anticipates. And Finch's mysterious birthday present of a key to Reese becomes a little less mysterious when Reese learns to where that key unlocks.
Finch gives Mr. Reese the day off as it's his birthday and chooses to work the new number with Fusco. FBI start looking into the murder of Jessica's husband.
- Reese flashes back to the period when he left the CIA. He is on a bus and has a wound to his stomach.
It is Reese's birthday, so Finch sends him away to enjoy the day. After he leaves we see the machine has spit out the name "Karen Garner."
Reese plays a board game in the park with a older blind man named Han. He shows him his only present was the key Finch gave him.
Special Agent Donnelly tells Carter about a new piece of DNA triggering something from a cold case. Donnelly thinks the murderer of a real estate developer named Peter Arndt could be his mystery man and wants her to help with the case.
Finch calls Carter and they agree to meet. She tells him about the case and Donnelly. Finch thinks she should help the case in order to help their "mutual friend." He had wanted to talk to her about something, but blows it off. The woman who waited on them was Garner.
Back in 2011 Reese is at a hospital looking for Jessica Arndt. He's told she was killed two months earlier in a car accident. The nurse gives him Jessica's husband's number.
Finch has Fusco look into Garner, who he thinks is probably using an alias. Finch tells him not to include Reese in this task.
Carter drops by Arndt's place. Donnelly says Arndt had been involved in some shady business dealings and was in with some loan sharks His wife was killed two months before he want missing. No body was ever found. Since the scene was so messy, Donnelly thinks it was his subject's first job.
Fusco ends up losing Garner while tailing her. Finch tells him he'll take over.
Finch tries to find Garner at her place of work. A U.S. Marshal named Jennings follows Finch out of the bar and says Garner's name is actually Atkins, and she's a wanted fugitive. The Marshal starts asking a ton of questions and at the last minute Reese shows up pretending to be a cop to get Finch, who he tells Jennings is his "C.I.," out of the situation.
Finch, telling Reese he wanted to keep him out of this case because of certain "sensibilities," thinks Garner lives with her threat, as her number kept popping up every few months.
Reese drops by to see Garner. She pulls a gun on him and he says he can help her. She says her real name is Sarah and Finch calls with word that her last name is Jennings -- the husband she's running from is the Marshal. Reese tells Sarah he can make it so she doesn't have to run anymore.
Carter is shown the Arndts' accident report.
Flashback to Reese spying on Arndt and breaking into the house after he leaves for work. Reese listens to old messages from Jessica on the Arndts' answering machine. It's apparent that Jessica seemed to be in an abusive relationship.
Carter is shown Jessica's x-rays. It seems as if her husband actually killed her after she had called Reese and then staged the car accident to cover it up.
Finch tells Reese Jennings has been in trouble for excessive force and had trumped-up the charges on Sarah to help track her down. Reese promises he'll show Jennings "what a real monster looks like."
Reese walks into the Marshal NYC field office and coolly, single-mindedly, muscles his way to Jenning's area. He puts a gun to Jennings' head and says if he comes after Sarah again he'll kill him. Finch sees that Sarah has snuck out the window of her safe house.
Sarah tries to purchase a train ticket. When the cashier acts strangely, she bolts but several officers grab her as she attempts to access the departing trains platform and hold her until Jennings shows up.
Finch uses a WiFi detector to locate Jennings' car. He's trying to take Sarah out of the city.
Carter and Donnelly pay a visit to Jessica's mother, who wasn't aware of the kind of trouble Arndt had been. Donnelly hears about Reese tearing up the Marshal's office and leaves. Carter calls Finch. She seems surprised that they weren't able to intervene before Arndt killed Jessica. Jessica's mother references a "fling" Jessica had with a soldier before Arndt. She gives Carter permission to look through Jessica's things. Carter finds a photograph of Jessica and a uniformed Reese together.
Flashback to Reese watching home movies of Arndt and Jessica.
Carter calls for help from an old friend on getting a background check on Reese.
Finch is concerned with Reese's mood and wants to bring the police in the situation. Reese isn't interested.
Carter calls Finch, who tells her about Reese going after Jennings.
Jennings, with Sarah under his control, checks into a motel. She's terrified. Jennings plays a sadistic game with her, and then starts to hit her. Reese breaks down the door, quickly disables Jennings and tells Sarah to leave. A bloodied Jennings tells Reese it will never be over between him and Sarah. Reese says "it's over for you" and knocks him out.
Carter pulls Reese over on a lonely stretch or road and asks to look in his trunk. She wants him to let her take Jennings in. He wants to take care of the situation and "do what needs to be done." She lets him go.
Flashback to Reese waiting for Arndt at his home when he returns. Reese starts talking about losing Jessica and then goes after Arndt.
Reese tells Finch he took care of Jennings. He asks Finch if Jesssica's number came up. Finch ducks the question. Finch gives Reese a card that says "Harold Wren, Universal Heritage Insurance." There is an address on the back.
Carter is sent Reese's file, but without reading it she shreds it, yet keeps and puts the photo of Jessica and Reese into her inside jacket pocket.
A warden from a Mexican prison calls with word that a U.S. Marshall named Jennings dropped off a fugitive who because of a drug charge will be in jail for a very long time. He mentions that there are several other Americans in his prison.
Reese uses the birthday present key to enter a spacious apartment. It overlooks the park where he spends time.
In 2011 on his way out of the hospital after learning of Jessica's death, Reese almost bumped into Finch. He was there in a wheelchair following the numbers of Jessica and Reese. He mutters "I'm so sorry."