It never quite hits you until the final episode is over, how long certain shows have been on the air. "Person of Interest" only had five seasons, which is nothing next to "Big Bang Theory," but it's very rare for any kind of cyberpunk science-fiction show to last so long. It was also extraordinary for how it changed over the years. In 2011, when it began, it maintained a certain ambivalence about the surveillance state. Then came Edward Snowden's disclosures in 2013, and the world changed. By 2016, "Person of Interest" became a cautionary tale about privacy and security. Going back through the earlier episodes felt positively nostalgic.
Episodes are listed below unranked and ordered by airdate. Moderate spoilers ahead.
"Witness" - The first season of "Person of Interest" was also its most formulaic. It strictly followed the standard case-of-the-week format, with only the occasional smattering of back story to help flesh out the main characters. However, "Witness" introduced a recurring villain, Elias, who would prove so charismatic that he outlasted nearly everyone else on the show. The episode itself has some great action sequences, a fun twist, and the ongoing conversations between Reese and Elias are very enjoyable.
"Relevance" - Another introduction episode, this time for Agent Shaw, who is working one of the Machine's relevant numbers on behalf of the government. We see everything from her POV, including the efforts of Reese, Finch, Carter, Fusco, and Root. The departure from formula allows us a glimpse into a different part of the Machine's operations, and the shady way that the information is being used by the Pentagon. I wasn't a fan of Shaw yet at this point, but she definitely made a strong first impression.
"Zero Day" - By the end of the second season, the history of Finch and the Machine had almost been fully laid out through flashbacks. However, they saved the juiciest events for the final two episodes. These are coupled with a struggle over control of the Machine in the present day, which culminates in a flashy showdown in the New York Public Library where Root gets to show off her guntoting skills. It's a whole lot of satisfying payoff that neatly sets up the events of the next episode. Speaking of which...
"God Mode" - Harold Finch has always been my favorite character because he's such a powerful and tragic figure. This is the episode that fully spells out the origins of his crusade to save "irrelevant" lives. We also get to see the full power of The Machine as "god mode" is activated, allowing Reese and his allies full access to its resources as the enemy close in on the physical location of the Machine. With the amount of closure offered, the series could have ended here and I would have been completely satisfied.
"The Devil's Share" - It starts with a knockout opening sequence that pairs scenes of the characters grieving with the Johnny Cash cover of "Hurt." And it closes with one of my favorite scenes of the entire series - Carl Elias paying tribute to a fallen friend before exacting a very cold revenge. He's the answer to the question of who among our heroes should dirty their hands to bring down a monster after the unthinkable happens. Reese and Shaw come out with their souls intact, but of course Elias's soul was lost long ago.
"Lethe" - A quieter character-building episode for Finch, but an important one. We learn about his father, his early experiments with computers, and his initial jaunts into troublemaking. I wish we'd seen more of the younger Finch, but this lone appearance just makes the episode all the more special. Saul Rubinek also guest stars as the ailing father of the Samaritan A.I., the latest number. And then, because the show is running headlong into its next arc, we're introduced to Camryn Manheim as the show's newest villain.
"Aletheia" - Notice that this is the third of three episodes that aired successively from the third season on the list. These transitional episodes were "Person of Interest" at its best, as it said goodbye to HR and dove headlong into government and corporate conspiracies. There's some really nail-biting sequences here, specifically Control's torture of Root and what happens to poor Arthur. Team Machine loses, and loses badly this week. And two episodes after losing a major cast member, it really felt like anyone could go next.
"Deus Ex Machina" - The final episode of the third season caps off an excellent year and welcomes the show's biggest villain, Samaritan. After weeks of trying to prevent the Machine's rival from coming online, and putting everyone through the wringer, we still end up with at worst case scenario. This is a major turning point for the series, and the whole format of the show is forever changed, in a good way. We end with the best "Person of Interest" cliff hanger, as every single good guy is left in limbo - including the Machine.
"If-Then-Else" - Probably the most famous episode of the series, as it tells its story from the Machine's point of view, and offers some new insight on how the A.I. thinks. With its assets stuck in the middle of a bad situation that is about to turn violent, the Machine needs to decide the best way to direct them to safety. It does this by running simulations of as many possible future scenarios as it can - but it can't foresee everything. And for such an emotionally fraught episode, it has what has to be the funniest gag too.
"The Day the World Went Away" - Not quite the finale, which I wasn't completely happy with, but this is the end of the line for two major characters and sets everyone up for the quickly coming end. The final season suffered a bit from a lower budget and fewer episodes, but they mustered up enough resources to make this one something special. Finch's number is up, and the stakes are very high. So we get a big car chase scene, a chilling monologue, Root with big guns - in short, all of my favorite things.