Finch and Grace meet at a coffee shop and she talks about how she saw the famous painting The Red Tower when she went to Italy. She talks about how it inspired her to become an artist and explore mysteries, and she asks Finch where he's traveled. He admits that he made it to Venice after college but avoids saying anything else.
Finch takes Bear to the park for a walk but uses the opportunity to watch Grace as she leaves her apartment. As she walks down the street, a nearby phone booth rings. By the time Finch answers it and gets a new set of Numbers from the Machine, Grace has walked off.
Back at the library, Finch informs Reese that they have two Numbers to investigate. They belong to a married couple, Sabrina and Daniel Drake. The Drakes own a publishing company and have been married for twenty years. Drake was born poor and earned a full scholarship to get through college. Finch has run a background check and discovers that a militia leader, Wade Huggins, has made threats against the publishing house after it published an indictment of the group. Finch goes to the Drakes' home while Reese enters the publishing house office with an RFID duplicator so he can scan an active card and access any offices in the building.
As Sabrina and Daniel arrive for a meeting, Reese comes in behind them. As he goes up in the elevator with them, Finch says that he's made an appointment that he plans to break. Reese is noted as his assistant so that he'll have an excuse to wait in the lobby. As they go up in the elevator, the Drakes bicker and Sabrina warns her husband that Henry Brooks, the man they're meeting, likes to show them up by getting their early.
The Drakes meet Henry in a conference room and he insists that they should sell the company because it's losing money. He assures them that the deal is legit but Sabrina isn't interested in selling the company. As Reese listens in after cloning their cell phones, Daniel tentatively suggests that they see how the board votes on the sale. Henry points out that their the majority shareholders and that the board vote is meaningless. As he leaves, Finch checks Henry's background and tells Reese that Henry was the first investor in the company and owns 5% of the shares.
Finch enters the Drakes' apartment by posing as an IT worker. Remodelers are in working on the kitchen and Finch electronically taps both of the Drakes' computers. Reese reports that the Drakes have separated and Finch has Reese follow Sabrina while he checks on Daniel.
At the station, Fusco is making a private call and tells the person that he'll meet them that night. Carter comes in as Fusco's phone rings. When he sees that it's Reese's phone number, he sends it to phone mail. A suspicious Reese calls Carter and asks what is going on with Fusco, and she admits that he's been acting jumpy. Reese then has Carter check on the militia and she informs him that they've already got word that the group is holding a protest at a book signing hosted by the publishing house.
While Finch follows Daniel as he leaves a restaurant, Reese sees a man approach Sabrina's car, attached a bomb underneath, and walk away. Reese removes it and walks into an alleyway, working to disarm the bomb before someone calls the cell phone triggering device. He cuts it off just as the cell phone rings, and Reese makes a note of the phone number. Meanwhile, Finch spots Daniel taking a call a different cell phone than his regular one, one that they haven't cloned. However, Daniel walks past Finch as he talks to Santiago, the man at the other end, and tells Santiago that he'd better handle things if he wants to collect his fee. Reese, listening in, realizes that Daniel hired Santiago to kill Sabrina.
As the Drakes take a limo back to their office, they argue over the sale of their company. Sabrina thinks her husband is spineless while he insists that he's just being fiscally prudent. Meanwhile, Finch examines the bomb and tells Reese that it's similar to one that the militia describes in their handbook. Reese figures that Daniel hired Santiago to build the duplicate bomb so that they could frame the militia for Sabrina's death, and the company shares would go to Daniel upon her death. Finch does some digging and confirms that a Nestor Santiago has had multiple phone conversations with Daniel. The two men grew up together and Santiago spent time in prison. One of Santiago's arresting officers, Cal Beecher, works at Carter's precinct and Finch calls her for some assistance.
Carter talks to Cal and gets some background on Santiago. The officer explains that Santiago was a small-time drug dealer who ended up his own product and was arrested during a B&E. However, Santiago had an expensive lawyer who got him off with a reduced sentence. Carter admits that she can't tell Cal much about the case and he says that he understands. However, he reminds her that she now owes him a favor and promises to do some checking on what Santiago is currently up to.
Reese follows the Drakes to the book signing, where the militia group has already gathered. Finch figures that it's a good time for Santiago to make another murder attempt and make the militia look responsible. Reese spots a sniper in a nearby building and moves in, but Finch tells him that he's intercepted a text message... from Sabrina to the sniper, giving him the word. Reese shoves Daniel out of the way, faking a casual accident, and the sniper misses. By the time Reese catches up to him, the second killer has made good his escape. Reese and Finch realize that the Machine gave them two Numbers because the Drakes are planning to kill each other.
Finch meets Nathan at a restaurant and his partner comments that he's running late. He jokingly asks if Finch had a date and then realizes that he did. Finch avoids talking about it and Nathan goes along with it, telling his partner that a little mystery goes a long way. Finch asks about Nathan's wife Olivia and Nathan admits that he saw her recently and couldn't even remember all of the lies that he told her. He tells Finch that the truth inevitably catches up with everyone.
Finch considers letting the Drakes kill each other, pointing out to Reese that they have innocent people to help. However, he admits that the Machine hasn't given them a new Number. Meanwhile, Finch tries to call Fusco and discovers that the detective has taken the battery out of his phone. Reese figure that something is wrong and has Finch trace Fusco's last known location from the GPS in his phone.
Thanks to their mutual friend Larry, Fusco is on a blind date with a woman, Rhonda. They end up at a fancy restaurant with gourmet food that neither one of them much likes. They talk about their children and Fusco admits that he doesn't see much of his son because of his long hours. Rhonda, clearly interested, asks about his job but Fusco awkwardly avoids the question. Finch has Fusco paged to the phone and tells him that he needs to work on his conversational skills. He tells him to keep an eye on Sabrina at her company office and put his cell phone battery back in his phone. Fusco goes back to the table and tells Rhonda that he has a stakeout, and she understands because she has a cousin who is a cop. She suggests that she go with him and that they pick up some falafels on the way, and Fusco eagerly accepts the offer.
Carter and Reese set up surveillance outside the Drake home and talk about marriage and love. Speaking from experience, Carter talks about how it's easy for one person in a marriage to change and fall out of love with them. Reese wonders if she's considered starting up new but Carter says that she doesn't have any spare time between her job and her extracurricular activities with Reese. When she asks Reese about his love life, he avoids the question and Cal calls her before she can pursue the matter. Cal tells her that Santiago boosted a deli van to get into the publishing house and she thanks him for their help. Someone cuts the power in the house and they realize that Sabrina's hired killer is going after his target.
As Fusco and Rhonda stake out the publishing house, Fusco describes one of his more memorable cases and finally thanks Rhonda for coming out with him. She's glad to be with him as well, but they're interrupted when Finch calls Fusco and tells him that a deliveryman has entered the building.
The killer is breaking into the house when Reese and Carter find him. He fights Reese but Daniel comes out, distracting Reese. The killer slips away and Reese punches Daniel unconscious when he demands answers and throws him in the trunk of his car.
Fusco enters the building and finds Santiago, posing as a deliveryman delivering deli food. Santiago opens fire on the detective and runs off, and Fusco finds Sabrina as he chases the killer down. He gets her out of the building just as Carter and Reese pull up. Reese tosses Sabrina in the trunk with Daniel just as Rhonda returns with falafels. Reese gets in the car while Carter introduces herself as Fusco's partner and then takes off with Reese.
Reese takes the Drakes to a safehouse and ties them in chairs. As they argue back and forth, Reese finally tells them what the other has been up to. They admit that they have no way to contact their respective killers and start arguing again, and Reese goes into the next room where Carter and Finch are watching through a one-way mirror. Reese left them alone because he figured they could use some counseling, and Finch suggests they speed things up with a different approach.
Fusco takes Rhonda home and she thanks him for the good time. She says that she'd like to do it again and Fusco tentatively agrees as they kiss goodnight.
Reese blindfolds the couple and Finch goes in and puts some food and wine on the table between them. He explains that he helps people even though sometime they don't deserve it, and suggests that they're just a couple who grew frustrated, and that frustration turned to hate. Finch puts down a photo of the couple in their early days that he took from their home earlier, removes their blindfolds, and leaves.
Grace is waiting for Finch at a restaurant when a bike messenger gives her an envelope. It's from Finch, inviting her on a birthday scavenger hunt. She eagerly sets out across the city, following the clues at each new location, and finally ends up at the Guggenheim Museum.
Sabrina and Daniel talk about how they were at a beach house when the photo was taken. Daniel mentions that Sabrina was still pregnant at the time and she suddenly calls out to Reese, saying that she'll tell them what she can about her hired killer. Reese comes in and she explains that she hired the killer through a security firm. She tried to call off the murder after the failed bookstore signing but the phone number was disconnected. Daniel admits that he tried to call off Santiago but couldn't reach him, either. Reese cuts them loose and explains that he's going to take them home and use them as bait to draw out the killers.
Finch is waiting for Grace inside the closed museum. She thanks him for the birthday surprise but he says that it isn't over yet and takes her through the empty halls to the art gallery. Hanging on the wall is The Red Tower and Finch claims that an anonymous donor gave it to the museum. Smiling, Finch wishes Grace a happy birthday.
Reese has the Drakes stand in front of a window so the killers can see them. Meanwhile, Fusco complains that Reese has no right to look into his personal life. Reese disagrees and tells him not to be so melodramatic, and then locks the Drakes in a pantry. The couple talks about what happened with the pregnancy and how they lost their first child. Sabrina thought that Daniel blamed him, while he admits that he drew away to respect her privacy. They both realize that they didn't say what they were thinking. Sabrina wanted to keep the company because it was the only thing she had left when she thought she lost Daniel, while Daniel wanted to break off entirely from the past. The couple agrees to try again when they get out of their current predicament, and apologize for having the other one killed.
Santiago brings in two men and Carter and Fusco engage them in the stairwell. Carter takes down one and another one shoots Fusco in the chest. When Carter tries to get to her partner, Santiago opens fire.
Sabrina's killer goes to the remodeled kitchen and prepares to open the pantry door, but Reese arrives and attacks him.
Santiago closes in on Carter but Fusco, who was wearing a bulletproof vest, guns the killer down.
Reese finally grabs a nailgun and shoots the hired killer in the shoulder, and then pins his foot to the floor. He then beats the man unconscious.
The next morning, the police take away the Drakes and the surviving killers. Cal comes by to check on Carter, who thanks him for his help. He points out that she still owes him and suggests she accept a dinner date with him to make up for it. Carter hesitates and then agrees.
Back at the library, Finch puts away a photo of himself and Grace as Reese comes in. He tells Reese that the Drakes are invoking spousal privilege so they can't testify against each other. Reese figures that the Drakes will hire some expensive lawyers and get minimal jail time at best, and points out that it's a lot of trouble just for two people to figure out they love each other after all. As Finch limps away, he says that anything is worthwhile when life gives a person a second chance to be with the one they love.
Grace and Finch leave the Guggenheim and she realizes that he's upset about something. They sit down and Finch tells her that she should know what he does for a living. Grace assures him that nothing he could say would change her feelings for him, but suggests that he do it when he isn't upset. Finch agrees and Grace tells him that they'll discover the mysteries of life together, and then kisses him.