We've described Person of Interest as a superhero show, where the heroes' superpowers come from a computer — but last night, more than ever, we got to see Finch as a superhero hacker. And he helped with the origin story of another hacker superhero, who can achieve greatness if he just overcomes his self-destructive tendencies.

It was basically pure delicious hacker candy. Spoilers ahead...

"2πR" basically proved that the show works just as well without Mr. Reese around — although I sort of missed seeing Reese beating up random mooks or shoving people into his car trunk as A) marriage counseling B) interrogation or C) a negotiation tactic or D) just random yuks. Mr. Finch is more than able to carry the bulk of the show on his slender shoulders, and in fact last night's outing helped cement Finch as the real damaged hero of the show.


Of course, "2πR" is sort of an overstuffed mess. There's a kid named Caleb who's a super math genius and brilliant computer programmer — and he's not only developed a brand new compression algorithm that's going to revolutionize the Internet, he's also a drug kingpin in his spare time. He's damaged and guilt-ridden because he was horsing around on the train tracks with his older brother, and the brother got hit by a train. So Caleb is selling tons of ecstasy to teens and reinventing online streaming video, to generate a ton of money for his alcoholic mom, so she's taken care of — and then he's going to kill himself when he's the same age, to the day, that his brother died.

There's some nifty misdirection in there, like we think that the two kids who are dealing drugs for Caleb are actually the ones who pushed his brother in front of the train — but actually it was Caleb's fault. And we think that Caleb's computer science teacher is stealing his work, when in fact he's acting as a frontman for Caleb, at Caleb's request. But it sort of falls apart in the end — like, what happens to Lorenzo, the evil drug dealer who swears to kill Caleb for selling drugs on his turf? Does Lorenzo just suffer from really bad narcolepsy and fall asleep in the middle of searching for Caleb? Or does Fusco deal with Lorenzo somehow off screen? The "drug dealer" subplot just sort of fizzles, in a confusing fashion.


But on the other hand, none of that was what the episode was really about. It was about Finch seeing something of himself in this young damaged "reckless" prodigy, and reaching out to him. And there was so much awesome nerd goodness in the scenes where Finch becomes the substitute math teacher for Caleb's class, and tries to teach the kids how to get around their regular, crappy math teacher's busy-work assignment. Also great: Finch telling Caleb how to make his strings better by using atomic variables for multithreading. And we even get a bit of the classic "substitute teacher inspires bored kids" goodness, with Finch explaining in a somewhat woo-woo but still lovely fashion how pi contains every other number in the universe and thus every possible word, in every possible combination. It's all just in this one circle, maaaaan.

And meanwhile, there's an intriguing new bit of backstory — the computer science teacher, who was a mediocre coder himself but sees greatness in Caleb, talks about how hackers tested the limits of computer systems, until some of them went too far and were sent to jail. And there's talk of a mysterious hacker hero from the days of the ARPANET, who "turned the whole thing inside out" and made sure the Internet would always be open — and who never got caught. And at the end of the episode, Finch hints that he might actually be that mysterious hacker, who did it all on a homemade computer. Could it be? Did Finch actually give us the Internet as we know it?

But first, the story culminates in a great scene where Finch talks Caleb out of offing himself, by talking about how they've both made terrible, costly mistakes — and those mistakes are part of them, but they're also why they won't believe anyone who says they can't change the world. Mr. Finch refers to the Machine as his biggest mistake, and says it brought him here to help Caleb. He says the thing about the world is it doesn't have any extra pieces, it's like Pi — it contains everything. It's actually quite a moving scene, and it ends with Finch saying that he once thought that leaving would make it easier on everyone, too. And he learned otherwise.


I really love Finch mentoring this young genius and helping him to grow up in his image. For a show where every episode is launched by a new number, it's neat to have an episode where numbers are at the center of it. And Finch tells Caleb, in the end, that it's a new era and things are going to get really weird soon, and he should be careful with his code and choose his friends wisely.

(This sort of echoes a bit from early on in the episode, when Fusco says that ten years from now, today's net-savvy high-schoolers will be running the world, with their sexting and their crazy drug tweets. There's a hilarious bit early on where Finch force-pairs with a bunch of students' phones and is appalled by what he reads.)


Meanwhile, we barely see Reese in this episode — but Carter is forced to do a bit of dirty work to keep the FBI from figuring out which of their four suspects is the Man in the Suit. (The FBI does DNA samples and fingerprints, but doesn't bother to X-ray the suspects to see which one of them has broken every bone in his body and stuff.) I love seeing Carter get all va-va-voomed up to seduce a businessman who looks enough like Reese that his DNA could plausibly be a substitute, then drug him and swab him. Seriously, the Sexy Carter scene pretty much made my day. And Carter's reward for getting Reese off the hook: Now she has to take charge of interrogating him and the other suspects, and try to break him using her Iraq War-era chops.

This should be interesting.