Recap / Person of Interest S02 E11

Season 2, Episode 11:

2-Pi-R

"The thing about the world is that it doesn't have any extra pieces. It's like pi, it contains everything. You remove a single piece... no circle."

— Finch.

With Reese now in FBI custody, Carter takes it upon herself to ensure that he is not identified as the Man in the Suit. Meanwhile, the numbers never stop coming in, so Finch heads Back to School as a substitute teacher and enlists Detective Fusco's help to protect the latest POI; an underachieving teenage computer genius.

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Tropes present in this episode include:

• Alcoholic Parent: Caleb's mom.
• All Up to You: With Reese in FBI custody, it's all up to Finch and Fusco to save the numbers from Irrelevant list, and it's up to Carter to make sure the FBI doesn't discover his identity.
• Alternate Company Equivalent: Caleb is basically a younger Finch while his teacher fills in for Nathan Ingram. Even Finch sees the similarities.
• Applied Mathematics: According to Finch, all of the world’s infinite possibilities are contained within the mathematical constant Pi. He also states that his phone number is contained somewhere in the first 3000 digits.
• Arbitrarily Large Bank Account: Finch arranges for the teacher he's replacing to win a trip to a conference in Maui.
• The Atoner: Finch, for making the Machine. Sometimes however your mistakes can surprise you.
• Badass in a Nice Suit
  Warden: They're terrorists? They look more like investment bankers to me.
  Donnelly: Well, warden, three of them may be. But one of them is the most dangerous criminal I've ever pursued.
• Camera Spoofing: Carter does a better job of breaking into an evidence room than Fusco did.
• Cliffhanger: Carter is given the job of interrogating the suspects, starting with Reese.
• Crazy-Prepared: Reese enters his holding cell to find that Finch has arranged for a mobile phone to be planted there. He states that he already had a plan in place to get Reese out of prison if he were arrested.
• …But He Sounds Handsome: Implied by Finch when he talks about the person who hacked Arpanet, but not stated outright.
• Demoted to Extra: Reese appears briefly at the beginning and at the end of the episode.
• The Dog Was the Mastermind: In true Person of Interest style, that new drug lord that's been dealing drugs at the high-school? It's Caleb.
  • Finch mentions that the infamous hacker who hacked the Arpanet in the 70s was a "kid with a homemade computer".
• Everyone Hates Mathematics: Except Finch, who is aghast at the idea that it's being done as class punishment.
• Femme Fatale: Carter plays this role to get access cards off of a bar-cruising FBI agent. It's scary to see how easily she slips into the role of a giggly floozy.
• A Friend in Need: Finch tells Carter he has a plan to get Reese out of prison, but finds that Carter has already pulled his fingerprints and has a plan in place to fix the DNA.
• Have You Told Anyone Else?: Subverted; when the teacher is going to sell Caleb's program, the man he's selling it too asks if anyone else is involved, implying that he will murder Caleb to keep all profits for himself. Turns out he had no intention of taking credit for Caleb's work.
• Head-Turning Beauty: Carter gets some open admiration when she walks into a singles bar in a cleavage-revealing blue dress.
• Hope Spot: It looks like Reese is about to be released from prison. Not if Donnelly has anything to say about it.
• Institutional Apparel: The Man in the Suit becomes the man in orange prison overalls.
• I Never Said It Was Poison: Finch knows a home-made computer was used to hack the Arpanet, even though it's never been mentioned anywhere else.
• Mouthful of Pi: This one was obvious just based on the title, though it was downplayed more than usual.
• Mundane Made Awesome: Finch's explanation of Pi is an in-universe example.
  "Pi. The ratio of the circumference of a circle to its diameter. And this is just the beginning. It keeps on going—forever, without ever repeating. Which means that contained within this string of decimals is every single other number. Your birth date, combination to your locker, your Social Security number. It's all in there somewhere. and if you convert these decimals into letters, you would have every word that ever existed in every possible combination. The first syllable you spoke as a baby, the name of your latest crush. Your entire life story from beginning to end. Everything we ever say or do... all of the world's infinite possibilities rest within this one simple circle. Now, what you do with that information... what it's good for... well, that would be up to you."
• My Card: Finch does his own paranoid version, his phone number hidden in Pi where only a Teen Genius could find it.
• Obfuscating Stupidity:
  • Caleb is really a Teen Genius whose computer coding skill impresses even Finch, but he intentionally gets low grades to hide it.
  • Fusco asks Finch why anyone would want to hide the fact that he's a genius, while talking to a man who's been doing this since 1980.
• Oblivious Guilt Slinging: Donnelly tells Carter she's the only person he can trust.
• One-Scene Wonder: the transit cop who investigated the death of Caleb's brother.
• Properly Paranoid: Donnelly correctly assumes the evidence has been tampered with. Unfortunately, he's not paranoid enough, as he goes to Carter for help interrogating Reese, as she's been chasing the Man in the Suit from the beginning.
• Retcon: A comment made in Season 4 implies that criminal mastermind Dominic also took inspiration from Finch's pi speech, though obviously Winston Duke isn't playing one of the students, having not been cast at the time.
• Short-Distance Phone Call: Finch and Fusco realise they're tracking the same person when they run into each other while talking on the phone.
• Shout-Out: Caleb says that he has no intention of standing on a table for Finch, a reference to Dead Poets Society.
  • Caleb puts on a bit more of an accent when he comments about Finch going through the trash, which comes across as a reference to Good Will Hunting.
• Shrouded in Myth: Mention is made of the greatest hacker of all time, a genius who hacked the Arpanet in the 70s, ultimately causing it to become the internet of today rather than a government-controlled network, and got away with it because the government could never identify who did it, much less catch him. As foreshadowed, it was Finch.
• Single Tear: Caleb when Finch talks him out of killing himself.
• Slipping a Mickey: Carter does it to her date at the bar to get a sample of his DNA.
• Talking Down the Suicidal: Finch for Caleb.
• What Happened to the Mouse?: The subplot concerning Caleb's conflict with a local gang for running a drug operation in their turf is never resolved.
  • Fusco tells Finch over the phone that he'll take care of it; we'll just have to assume that he did.