Person of Interest: Zero Day
December 29, 2024 2:40 PM - Season 2, Episode 21 - Subscribe

Reese and Finch realize that a virus has rendered The Machine erratic, causing it to issue numbers irregularly. As they race against the viral countdown, the team searches for an elusive tech millionaire. Also, Detective Carter's mission to bring Cal Beecher's murderer to justice lands her squarely within the sights of HR.

Day 4138

Reese is in a parked car listening to the police band scanner. He calls Finch at the library and reminds him that it's been ten days since the Machine sent the last number. Finch confirms that they have 20 hours remaining until the virus shuts down the Machine and tells Reese that for the moment the Machine is still functioning, but can't communicate with them. As they talk, a police report about a triple-homicide goes out over the scanner and Reese drives off to investigate.

Carter is called in to help with the shooting, which involved two of Elias' men and an innocent bystander. Detective Terney is working the case, and Carter tells him that Fusco is busy on another assignment. He tells Carter that the Russians are responsible. Terney asks if Carter is looking into Cal's death and assures her that he's there to help if she needs anything. Carter spots Reese standing nearby and goes over to talk to him. He offers his condolences on Cal's death, and Carter asks why he and Finch weren't warned about the murders by the Machine. Reese admits that a situation has come up but they're working on it, and Carter tells him to hurry up and resolve it. She admits that no matter how bad Elias was, the Russians are even worse.

In Washington D.C, Special Counsel is on the phone, saying that they haven't received a number from the Machine in the last seven days. He informs his superior that they've confirmed that the chip in Corwin's body came from Decima, and speculates that the covert tech company is trying to destroy the Machine. As Special Counsel finishes his call, Root comes back in with a gun and demands information.

Finch visits Nathan's apartment and his friend explains that since they sold the Machine to the U.S. government, he's been busy reorganizing their company. As they talk, Finch tells Ingram about his relationship with Grac, and asks him to look at the present that he bought her. It's a book with an engagement ring inside, and Nathan offers his congratulations. Finch is worried that Grace can't handle the truth about who he really is, and Nathan reminds him that he had legal troubles in his youth. He agrees with Finch that they can hire the best lawyers to defend him, but warns him that the government might not be happy to learn that Finch is his silent partner. Finch figures that they're done with the government, and Nathan goes to get some champagne to make a toast. As he leaves the room, his phone rings and Finch notices that his partner is receiving a SMS system message.


The next day, Finch is walking Bear when the Machine calls a payphone and gives him a new number. He calls Reese and tells him that their latest POI is Ernest Thornhill, the owner of a data entry company. Thornhill has apparently been buying up payphone franchises throughout New York City, and Finch admits that he's been unable to hack the company's firewall.

The two go undercover at Thornhill's company. While Finch poses as an IT worker, Reese talks with Thornhill's secretary and claims that he had a business appointment. The secretary says that Thornhill is away on business, and there's no record of an appointment. Reese says he'll check back later. Meanwhile, Finch checks the sheets of data that the workers are typing in and discovers that it's pointless gibberish, all printed out on dot matrix printers. As far as he can tell, the workers are simply transferring the data from one computer to another, and Reese wonders if Thornhill's company is a front.

As they talk, Root calls Finch from Special Counsel's office and asks what he did to the Machine, and why it isn't defending itself. Finch refuses to talk to discuss the matter, and Root suggests that they work together to save his creation. She mentions Thornhill and Finch wonders what she knows, and Root suggests that they exchange information.

When Reese and Finch go back to the library, they try to work out why Root is interested in Thornhill. Thornhill simply appeared out of nowhere six months ago, opened up a bank account with a deposit of one penny, and parlayed it into $20 million. Since then, he's been buying up payphone companies. Finch checks Thornhill's credit card records and discovers that he's rented a car to pick him up at JFK International that day when he returns to New York. As Reese goes to intercept Thornhill, he promises Finch that he won't let Root abduct him a second time.

Reese waits at the only road going from JFK to Thornhill's company. Finch tracks the Thornhill's GPS in his cell phone and Reese spots the rental car coming. Meanwhile, a man parks down the road from Reese and starts using his cell phone. An aerial drone closes in on Thornhill's car and Reese opens fire on the man. The drone operator drops his phone and flees, while the drone strikes and blows up Thornhill's car. Reese goes to the car and makes sure that the driver is okay, only to find the passenger seats empty.

Reese returns to the Library and Finch checks the phone the operator used. He confirms that it has a programming signature similar to that of the virus targeting the Machine, and they figure that Decima sent the man. Carter calls to tell them that the driver is in stable condition at the hospital. She's questioned some of Thornhill's workers and learned that none of them have ever actually met the Thornhill. Reese tells Finch that Thornhill must be a fake identity that someone is using. Finch disagrees and analyzes the only photo that they have of Thornhill. He discovers that it's a composite of three other photos. Finch has also checked the last email that Thornhill sent from his phone, in a public park. According to the security cameras, there's no one there. Finch recognizes the algorithm because he developed it for the Machine. They realize that Ernest Thornhill is a fake identity created by the Machine.

Finch meets Grace in the park and she paints a portrait of him. Once he turns off both of their phones, he takes her to a secluded spot. As the Machine tries to watch them from the nearest camera, Finch gives her the book and then gets down on one knee and proposes to her. Grace accepts, and the two kiss.


Finch insists that he took precautions to make sure the Machine wasn't creative enough to do something like create a fake ID. The only reason he can think of for the Machine to create a fake identity is so that it meets the residency requirements to own a payphone. As they talk, Finch receives a text message on his computer from Root, asking for a meeting. Rather than tell Reese about it, he tells his partner to check out Thornhill's apartment. Once Reese leaves, Finch calls 911.

Once Reese gets to the apartment, Carter calls him and asks why someone rented a car but didn't use it. Reese tells her that they have it under control and advises her to look into Cal's murder. As he hangs up, Shaw comes up behind him and holds him at gunpoint. When he asks why she's there, Shaw says that she's hunting Root.

Finch meets Root in the park near Grace's apartment, and watches as his fiancee leaves for the day. Root assures him that she doesn't have any intention of hurting Grace, and explains that when the virus countdown ends, the Machine will go into debugging mode. It will call a payphone in New York City and due to Finch's programming, it will give full administrative access to the person whomever answers the phone. Root knows all about Decima, which engineered the virus and doesn't want them gaining control of the Machine. When Finch hesitates, Root promises to kill Grace if he doesn't cooperate. He gives in but tells her that there won't be any killing.

Meanwhile, Simmons calls Terney at the station and tells him that Quinn wants Carter eliminated. Terney then approaches Carter and says that he has a lead on Cal's killer. She leaves with him, unaware that the Machine has been watching her through the station cameras. It tries to call Finch on a payphone. When he goes over to answer it, Root tells him that they don't have time to deal with it and takes him away.

Shaw informs Reese that Root has infiltrated The Program and gotten close to Special Counsel. As Reese starts to call Finch to warn him, the police break in and capture him. Shaw slips away before they can spot her, leaving Reese behind.

Finch is going to see Nathan and tell him that Grace accepted his proposal. He leaves a message on Nathan's voice mail and approaches his friend's apartment building just as Nathan leaves. Nathan checks his phone and clearly ignores Finch's call. Intrigued, Finch follows his partner to an abandoned library and goes inside after him. When he finds Nathan, Finch asks what is going on.

As Finch and Root walk down the street, Root figures that Finch programmed the Machine with a backdoor in case it crashed, so that the administrator would have unlimited access. Decima is trying to kill Thornhill because the CEO has been buying up payphone companies to gain control of any payphone that the Machine might use to make the call at zero hour. When she wonders how vulnerable the Machine is, Finch admits that the person who takes the call will have unlimited access for 24 hours. However, he's sure that Decima doesn't know which payphone the Machine will use for the call. As they continue walking, Root points out that Decima has men guarding every payphone in sight, meaning that the call will come to a phone in midtown. Even if Finch tells her which phone to use, they can't get to it. However, Root is confident that Thornhill has a plan so they don't need one.

While Reese awaits interrogation at the station, Shaw comes in posing as his lawyer. She plays a recording of Finch's call to 911, reporting a break-in at Thornhill's apartment, and points out that Finch wanted Reese out of the way. When Shaw asks if Reese can trace Finch, he admits that he put a tracking bug in Finch's glasses. Shaw then removes two guns taped to her back, gives one to Reese, and tosses her briefcase out into the hallway. The tear gas bomb inside explodes and they walk out, using water-soaked cloths for protection.
Root and Finch go to Thornhill's company. As she breaks in, Root realizes that the Machine created Thornhill to protect itself. When she sees the screens of code, Root realizes that the Machine has been protecting itself by downloading its own programming code and having the data entry operators enter it back in. Finch explains that when he developed the Machine, he realized that it had a personality and had imprinted on him like a child on a parent. Since he couldn't afford a Machine with human sensibilities, he designed it to erase its personality programming each day at midnight. As a defense, the Machine created a living external hard drive to backup its memory code. Root points out that even though it has survived, the Machine is all but crippled personality-wise by the constant loss and reloading of its personality programming.

Carter and Terney take two other officers to the house of Cal's suspected killer. The suspect comes running out and fires at Carter, and she shoots back in self-defense, killing him. Terney reluctantly calls in backup.

Reese and Shaw follow the tracker to Thornhill's company, only to find Decima's men there. When they shoot them down, they find Greer waiting for them. He refuses to stop the virus and explains that he found it on the laptop that Reese and Kara were sent to China to retrieve. Greer informs Reese that the man who designed the virus was Finch, although he admits that he hasn't been able to locate him. More Decima mercenaries arrive and open fire, and Greer slips away in the confusion.

Nathan explains that he bought the abandoned library and 14 others like it on Finch's recommendation. When Finch notices a board with photos on it, Nathan explains that he's been trying to save the "irrelevant" numbers given to him by the Machine. To Finch's shock, Ingram says he saved five people but lost seven, and explains that he couldn't let them die even though Finch and the government consider them irrelevant. All he can get from the Machine is their Social Security Numbers, and no indication that they're victim or perpetrator. Finch warns his partner that the government can track Nathan if they put their mind to it and tries to shut down the Contingency. Nathan asks Finch if he can look the next Number in the eye and say that they're irrelevant, but Finch insists that there's a greater good involved. He sadly says that people die every day, and they can't save them all. Unable to turn off the Contingency, Finch removes Nathan's Admin status. Finch walks away unaware that the next number on the screen is Nathan's.
Greer calls his mercenaries throughout the city and tells them that the virus has revealed which payphone the call will go to: the New York City Public Library.

Finch takes Root to the public library and shows her the phone the Machine will use. Two Decima mercenaries arrive to guard it so Root goes upstairs to the building's juncture box. She tasers the mercenary guarding it and tells Harold to intercept the call from there so they can save the Machine from Decima and from Finch's destructive programming. She plans to have the Machine tell her where she can find it and then she can go to save it.

As the police secure the crime scene, an IAB detective arrives and tells Carter that she's under arrest. Terney has already spoken with the IAB and told him that the suspect didn't have a gun. When Carter checks the crime scene, she discovers that the gun has disappeared.

Reese and Shaw follow Finch to the library and exchange shots with the Decima mercenaries. Root watches from the balcony and informs Finch that Reese has arrived. Meanwhile, Reese finishes off the last Decima henchman and checks his phone, and discovers that more mercenaries are on their way.

At midnight, the Machine reboots and goes into debugging mode. It calls and the phone near Root rings. She answers it, unaware that Finch has rerouted the call a second time and sent a text message to Reese to answer it. Meanwhile, Root tells the caller at the other end that she understands. She then tells Finch that they're going on a trip, and the fun is just beginning.

Reese answers the phone, and the Machine says, "can you hear me?"

Points of Interest

The first mention and "appearance" of Thornhill.

Similar to “Relevance” s2 e16, the title sequence is interrupted partway through as the Machine is beset by the virus.

The content of the Machine's memory, along with its own "identity", are deleted every night at midnight. 1.618 seconds later, it reinstantiates, completely new. Finch devised this daily function as a way to prevent the Machine from evolving, after he began to encounter anomalies and realized the Machine was imprinting on him like a child with a parent ("It started looking out for me, altered its own code to take care of me. It was behaving like a person. But the world didn't need a person to protect it. It needed a machine.") Despite this, the Machine demonstrates an instinct for self-preservation by creating the Thornhill identity as a means to store its memories through "an external hard drive made up of people and paper." The Machine's memories are printed every day before the midnight erase and then typed back in the day after by the employees at Thornhill's data entry company.

Finch says the Machine deletes itself and "reinstantiates 1.618 seconds later". 1.618 is not a random number but rather phi (ɸ), a "golden ratio" that is widely present in nature, where it creates Fibonacci spirals. It is commonly used in architecture and arts, where it creates aesthetically pleasing proportions.

At the end of The Machine's reboot process, it generates four lines of binary code. When it's converted to ASCII characters the phrase "Quis custodiet ipsos custodes" is revealed. Screenshot zero day binary. This Latin phrase is translated as "Who will guard the guards themselves?", a variation on the old axiom "Who watches the watchers?" In other words, who is watching the people who watch us all?

Michael Emerson noted ub the DVD featurette that the flashback in which Finch follows Ingram from a cafe to the Library is the first in which Finch wears his now-trademark vest. This marks the transition from Finch's old, happy life to his new secretive life to come.

Finch reroutes the Machine's call to its admin by accessing the telephone junction box. Once the call was established, he spliced the lines in order to create a "party line", where two or more subscribers share the same phone number, so that two persons can co-administer the Machine. Party lines are seldom used now, but were common in the early days of the telephone service, when phone usage was cost-prohibitive and phone lines were scarce.
posted by miss-lapin (12 comments total)
 
Love Finch's plans within plans
posted by DowBits at 4:11 PM on December 29, 2024 [2 favorites]


I love that/ find it hilarious that Shaw goes into a loud mission wearing stiletto boots. Root's wearing heeled boots, too, but at least they're chunky. Carter usually wears something practical.
posted by porpoise at 5:55 PM on December 29, 2024


OK, I forgot that there was another wonky title sequence in this episode!

My wife, who has never had any interest in POI whatsoever, was intrigued enough by this ep when she saw me starting to watch it that she sat down and watched the rest with me... then was game to watch "God Mode" a couple nights later.

(To be clear, it wasn't the title sequence that initially got her interested -- it was the fact that our little foster Pomeranian rather hilariously started growling at Bear when he appeared on screen with Finch early on, LOL.)
posted by Artifice_Eternity at 6:05 PM on December 30, 2024 [1 favorite]


The only dangling mystery in the series for me is the chip in Corwin's body. They mention it this once, but Alicia Corwin's activities are never brought up again. She has been living like a hermit and cut off from all modern electronics, but has a chip from Decima implanted??! Strange turn. Wonder what storylines got dropped in the writers room...
posted by techSupp0rt at 2:52 AM on December 31, 2024


Alicia Corwin was murdered by Root in the s1 finale.
posted by miss-lapin at 10:11 AM on December 31, 2024


Yes, Alicia is gone but nobody seems to dig into her involvement with Decima. The presence of an _implanted_ chip (and she is the only one in the series to ever have one, iirc, Decima or otherwise) has zero impact on the rest of the story. Seems like an odd inclusion, from a story-telling standpoint. When I saw it for the first time, I wondered and speculated about its implications, but was surprised that that tidbit was thrown away.
posted by techSupp0rt at 12:17 PM on December 31, 2024


I had completely forgotten about the chip. That's a very X-Files plot point.
posted by Artifice_Eternity at 2:49 PM on December 31, 2024


I don't want to spoiler as I know at least one person is a first time viewer so I'll just say lots of things in POI seemingly get dropped only to be picked up again much later. This could be one of them.
posted by miss-lapin at 6:00 PM on December 31, 2024


One of the amazing things about this show is how much it makes you come to care about the Machine. Root's reaction in this episode to the revelation that Finch programmed the machine to delete itself, the Machine hiring people to try to type up the code for its memories, hearing how the Machine imprinted on Harold... it's amazing how much pathos this show evokes for the machine.
posted by litera scripta manet at 10:32 AM on January 4 [4 favorites]


It's amazing how a group of really talented people can make you care about something that doesn't even have a physical embodiment for us to project onto like Wilson in Castaway. Root's outrage at what Finch did was so understandable to me. Here's this entity that's desperately trying to hold onto its sense of self!
posted by miss-lapin at 11:56 AM on January 4 [2 favorites]


These two episodes were SO GOOD.

Root's outrage at what Finch did was so understandable to me.

Same same same, and also at "you took its memories" a very sudden revelation that ROOT WAS RIGHT; that although Harold was guided by altruism for human life he had in fact behaved unspeakably cruelly to the Machine's new artificial life.

I'd mentioned back in S1/early S2 that I wasn't really connecting with Root as a character; hoo boy did that change.

The party-line business: I probably need to rewatch these 2 episodes because I really didn't get it on first-watch. Does the Machine really split its god-mode attention two ways simply because two people answer the call? Or is this all part of a deeper plan by Harold? or by the Machine itself?

Lots of things in POI seemingly get dropped only to be picked up again much later

Yeah, I think I mentioned from my first-watch perspective that the show seems very good at picking up dangling threads, but:
having watched through to the end, spoilers...Alicia's chip does indeed seem to be mostly a dropped thread. Or really, a little self-contained arc entirely separate to the later implantable-chip plotlines in S4/S5? Alicia's is a RFID chip in her shoulder; the S4/S5 chips are neural implants; different things. But yeah, I don't think the show ever really explains why Alicia had a Decima RFID in her, other than it being a narrative convenience to make a connection to Decima here.

posted by We had a deal, Kyle at 4:38 PM on January 6 [1 favorite]


Also, the business of the memory reset -- of the Machine being reborn every day as a clone of itself -- felt very on-brand for the Nolan family. A recurring theme for Christopher -- Memento; The Prestige -- and an idea that Jonathan went on to explore more in Westworld.
posted by We had a deal, Kyle at 6:40 PM on January 6 [1 favorite]


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