The Machine monitors Azarello as he makes a deal with the IAB to tell them everything they need to know about Fusco and his connections to HR.

Fusco drags Stills' corpse into the woods of Oyster Bay. Crying, he buries Stills in a shallow grave.

Booker University is holding an award ceremony for famous cardiologist Dr. Richard Nelson, this week's POI. Reese works the room posing as a waiter while Finch briefs him on the doctor.

After Nelson accepts his award, Molly, his daughter, walks out. When Nelson starts to go after her, he is intercepted by Brandon Boyd, a hedge fund trader with VAC Capital, and Dr. Garrett Rossmore, both of whom offer him a drink. Nelson apologizes to Rossmore for the decision of Nelson's independent review board that recommended halting the trials of a new statin developed by Philia pharmaceuticals.

After Beecher's funeral, Fusco accuses Simmons and HR of being behind Cal's murder. Fusco promises to take them down for the shooting, but Simmons tells Fusco that he no longer has HR's protection. He also informs him that Azarello has tipped off IAB about Fusco's connection to several murders.

As Nelson receives his congratulations from his protege, his nose suddenly begins to bleed. Reese comes over and gives Nelson a napkin. Nelson begins to stumble and drops his glass, and Reese helps him to a chair. Reese informs Finch of Nelson's symptoms.

At the police station, IAB Detective Joseph Soriano approaches Fusco and tells him to hand over his badge and his gun. Once Soriano locks Fusco up in an interrogation room, Carter goes in and asks him what's going on. Fusco tells her that it's none of her business and reminds her that when he tried to explain before, she said that she didn't want to hear him out. He advises Carter to stay away from him for her own sake. Carter gets a call from Finch and reluctantly steps out to take it. Finch offers his condolences on Cal's death and she wonders why they couldn't save him. Finch admits that he's not sure why and then asks for her help, but Carter refuses, saying she wants Finch to help her for once and show her how to clone a phone.

Nelson goes to his university lab and calls Molly, thanking her for showing up. When she objects to his work for the university, Nelson reminds her that it's the university that pays his salary and keeps a roof over her head. When his nose starts bleeding again, Nelson tells Molly that he'll get back to her. He starts vomiting up blood unaware that Reese is watching him from across the street. Weakening by the moment, Nelson calls 911 and tells the operator that someone has poisoned him. As he staggers outside, Reese approaches him but the doctor assumes that he's connected to the poisoning. The police arrive in response to the 911 call and Reese moves off before they can spot him. As the officers take Nelson to the hospital, Reese informs Finch that he may have arrived too late to save Nelson.

Soriano tells Fusco that they've received a tip that he's connected to Stills' disappearance. He wonders what Fusco's connection is to Stills, and Fusco says that they worked together coming up. He ended up in Homicide while Stills went into Narcotics.

2004 Stills goes looking for his partner and finds Fusco drinking alone in a bar at closing time. When Stills offers to take him home, Fusco says that his wife has filed for divorce and is asking for full custody of their son. Stills offers to put him up at his place and Fusco accepts.

Finch checks Nelson's lab with a Geiger counter and Reese recognizes Nelson's symptoms as the result of polonium poisoning. The substance has to be ingested and is fatal if not treated within an hour of administration. Reese goes to the hospital and meets with Nelson, telling him that he's there to help. However, Reese admits that there's no cure for polonium poison after the first hour, and that Nelson has less than 24 hours to live. Nelson wonders what he can do and Reese suggests that they look for his killer.

Once Nelson leaves the hospital, Reese advises him to get his affairs in order. They visit Molly, and Nelson apologizes to her for his mistakes, and tells her that the thing in his life he is most proud of is her.

Carter listens in on a cloned phone as Soriano tells Fusco that Azarello is claiming that Fusco was his inside man with Homicide. He has a video of Azarello explaining how Fusco worked with him and Stills. Fusco denies it, saying that Azarello is lying, but Soriano says that Azarello has provided them with all the details they need.

Stills calls Fusco after a drug rip off gone bad and explains that the dealer they were holding up for money wouldn't play along, so they shot him. Fusco is reluctant to help them, but Stills reminds him of their friendship and how he helped him when his wife dumped him. Fusco reluctantly agrees to help and shows them how to make it look like a legitimate shooting.

Finch calls Carter, who informs him that Boyd's company, VAC Capital, is under SEC investigation. VAC is accused of insider training after they sold their Philia stock just before the drug trial was halted. Finch passes the information on to Reese, and Nelson admits that VAC handles his moneys. The doctor admits that he told Boyd that the board was going to refuse Rossmore's recommendation, and Reese tells him that Boyd made $500 million from the inside info. The SEC investigation hasn't turned up Nelson's role -- yet -- and Reese figures that the company will eliminate Nelson to protect themselves. Nelson blames himself and figures that he deserves to die, but Reese tells him that he doesn't. The doctor says that he needs to talk to Boyd.

Boyd is leaving a nightclub and retrieves his car from Reese who is pretending to be the valet. Reese knocks out Boyd and shoves him to Nelson who is waiting in the back. Reese passes Nelson a gun and Nelson holds Boyd at gunpoint and Boyd admits that his boss, Vincent Cochran, was the one he told about Nelson. However, Boyd insists that he didn't know anything about the poisoning. He admits that he told Cochran, and Cochran said he would take care of Nelson. Nelson demands to know where they can find Cochran and Boyd finally directs him to an upstate lodge called the Wingcrest.

2005 Stills calls Fusco in on another drug rip off gone bad. When Fusco arrives, he sees that Stills and Azarello have killed several people. Fusco refuses to help them but another dealer hiding in the closet jumps out and attacks them and Fusco kills him in self-defense. Stills gives Fusco some of the drug money and welcomes him to their crew.

Soriano tells Fusco that Azarello has told them what he did to Stills, and that they found bleach stains in the trunk of the car that Fusco checked out the day that Stills disappeared. Soriano figures that Fusco wiped it down to remove DNA evidence of the murder. He then shows him the phone records they have showing that Fusco made a call from Oyster Bay at 2 A.M on the night that Stills vanished. Finally, Soriano shows Fusco satellite photos of the Oyster Bay area showing all of the spots where there is disturbed earth from the night Fusco was there. He tells Fusco that in the morning they're going to search Oyster Bay for Stills' body. Carter, meanwhile, has been listening in on the whole conversation.

Fusco goes to the restroom to wash his hands and finds Carter waiting for him. He tells her that he didn't kill Stills but that he's going to go down for it for the other things he did. He admits that he used to work with Stills and gradually became a dirty cop who killed people, but he's now changed. Carter says that she doesn't know who he is anymore.

At the lodge, Nelson sits down next to Cochran, who is having a drink and relaxing. Nelson asks Cochran if he recognizes him and then introduces himself as the man Cochran murdered. Cochran does not appear affected by the news.

Carter calls Reese as he goes through the wine cellar at the lodge. She asks how he's going to help Fusco and Reese says that he doesn't plan to do anything at the moment. He reminds her that Fusco is her partner, and Carter wonders if he knows what Fusco has done. When she says that Fusco deserves to be behind bars, Reese says that she'll have to decide what to do, if she does anything. Reese hangs up and Carter wonders what to do next.

Nelson explains to Cochran how polonium affects the human body and causes death. Cochran shows no remorse. Nelson tells Cochran that he knows the man doesn't care about investing in medical research, only in making money. Cochran says that all he did was dump the loser, and he always wins. Nelson says that he made a lot of mistakes in his life but he doesn't deserve to die. Cochran tells Nelson that the SEC investigation will die with Nelson, but Nelson says that he won't be the only one dying. He points out that Cochran's nose is bleeding, and Reese, dressed as the waiter who refilled Cochran's wine glass, hands him a napkin. Nelson tells his killer that he has twenty-four hours to spend his $9 billion fortune and suggests that he do so wisely.

The next morning, Soriano drives Fusco out to Oyster Bay telling him it's the "end of the line."

Nelson calls Molly from the lodge and he comforts her about a recent breakup but does not tell her about his poisoning. The doctor says goodbye, and Reese brings him a drink of the Scotch. Nelson thanks him for giving him one last chance and then promptly dies. Reese tells Finch that they've lost Nelson. They both wonder why The Machine didn't warn them in time to save Nelson, and Reese wonders who else they're missing.

As Simmons accompanies Fusco to a digging site, he tells Fusco that he's as good as dead. The cadaver dogs have sniffed out a grave but the officers have discovered that someone recently dug up the site. Soriano promises to connect Fusco to Stills' death, but Fusco insists that he's not a dirty cop and asks for his badge and gun back.

When Reese returns to the Library, Finch tells him that Fusco is "off the hook, for now". He has talked with Elias in Rikers, and Elias has "convinced" Azarello to recant his testimony against Fusco. Finch then brings up a monitor showing the progress of the virus attacking The Machine. Reese notices that Bear is gone and Finch tells him that there is another matter they need to discuss.

Fusco returns to the station and Carter comes over and hands him a file. She says that she wants a fresh set of eyes on it, but that she's tired after a long night. She walks off with Bear, both of them leaving muddy footprints, implying she dug up Stills' body. Fusco looks through the file and discovers that it has all of the information on Cal's death. The Machine tries to watch him on the station cameras, but it shuts down due to the virus, and its primary systems go offline.

Points of Interest

The Domain Awareness System used by IAB to find the disturbed ground was developed by the New York Police Department in collaboration with Microsoft. Its objective is to harness and analyze video feeds, license plate reader output and other data sources as part of an on-going anti-terrorism initiative. This system has several eerily similar attributes of the Machine, as detailed in an episode of the PBS documentary series Nova detailing the capture of the Boston Marathon bombers.

Both Quinn and the POI quote Plato.

The person of interest is a dying man trying to solve his own murder. This plotline is a variation on a theme from the 1950's film D.O.A. In that film, the protagonist was poisoned with a luminous toxin (most likely radioactive). DEnnis Quaid starred in a 1988 remake with the same title and basic plot.

Coincidentally, Dennis Boutsikaris, who plays this week's person of interest, played a character in similar circumstances on CBS's Elementary, in the episode "Possibility Two." Elementary, a contemporary reimagination of Sherlock Holmes, was broadcast immediately following Person of Interest and also is set and filmed in New York.

In 2006, Alexander Litvinenko, a former Russian intelligence operative, died in a manner similar to Dr. Nelson when he unknowingly ingested a lethal dose of polonium-210.

According to Business Insider, the fictional hedge fund in this episode, VAC Capital, bears some similarity to a company based in Stamford, Connecticut, called SAC Capital, which was under investigation for insider trading of certain pharmaceutical companies at the point of time this episode was produced. SAC pleaded guilty in November 2013, and is part of Point72 Asset Management since 2016.