This week’s episode of Person of Interest, “Zero Day”, begins pretty much where last week left off, with the virus propagating throughout the Machine’s systems and blocking Finch and Co.’s ability to receive numbers. What’s more, it appears that the virus is on some sort of a count down, and they only have a few more hours to figure out what’s going on.

I like where this situation puts Reese. Even without a number, he doesn’t give up on trying to help people. We meet up with him sitting in his car, listening to a police scanner on the off chance that he’ll overhear something he can act on. It’s a far cry from the character we first met, a broken man living on the streets of New York who felt completely powerless to change anything.

A number does eventually get through to Finch, for a high profile CEO named Ernest Thornhill. Except Thornhill is one elusive, and strange, cat. He has an office full of people who have never seen him who spend all day inputting what looks like garbage code off of dot matrix printouts into computers, and he’s been going around buying up every pay phone in the city.

It’s also apparent someone wants Mr. Thornhill dead, as they hijack a friggin’ drone and try to blow up his car. Luckily, Reese is on scene to help pull the driver out of the burning car and…no one else. Thornhill wasn’t there.

I wrote last week about the show’s ability to take a simple premise and deal with it in inventive ways, and this week gave us another great take on it. It turns out that Mr. Thornhill is…wait for it…THE MACHINE ITSELF. Apparently, it has the ability to perceive a threat and take measures to defend itself.

The show has dabbled with the idea of the Machine as potentially self aware before, and with the re-introduction of the delightfully amoral hacker Root, that concept gets taken up a gear here. Especially when Finch explains to Root what the machine was having it’s employees do with all those print outs. It isn’t garbage code, he explains, but the machine’s memories.

While building the system, Finch quickly realized that it was learning stuff irrelevant to its purpose, that it was developing an identity. In order to prevent that from happening, Finch built in a setting that deletes this “junk” data every night, effectively killing this identity. But the machine adapted, creating a ghost and starting a company and hiring employees to type its memories back into the system in a futile attempt to preserve itself. It’s a gripping, emotional scene, and one that presents a brand of science fiction that one doesn’t normally expect to see on television.

While Root is blackmailing Finch to help her in her undying crusade to “Free the Machine”, Reese teams up with Shaw. This is the crowd pleasing element of this week’s episode, as Shaw helps Reese escape from police custody by posing as his lawyer and smuggling in a couple of guns duct taped to her back. Shaw has been a ridiculously fun element on this show since her introduction, and her rivalry with Root is an interesting one. I’m hoping that next season has her becoming a more permanent fixture on the show.

It is revealed that the countdown is another of Finch’s fail safes, designed to reboot the system in the event of a threat. When the reboot is complete, the Machine will dial a payphone. Whoever answers that payphone will be granted unfettered control over the machine for twenty four hours.

Meanwhile, Carter continues to investigate the murder of fellow cop/ failed love interest Detective Beecher. She’s still dealing with the cognitive fall out from last week’s episode involving Fusco, but she has begun to worry about Finch and Reese’s inactivity of late. This hasn’t stopped her from making waves on Beecher, however. Another detective asks her about it, and offers his help.

Of course, the guy is dirty, and on a routine call it almost looks as though he’s going to put one in Carter’s back. Before he can, an armed perp busts out of the house and Carter has to shoot him. Unfortunately, once her superiors are on scene, the gun has been removed, setting Carter up for an internal affairs investigation.

This developement is a bit odd. Why was Carter’s fellow detective about to shoot her, if they were going to frame her, instead? I think the machine tried to intervene in this case, as it recognized the threat to Carter as she left the precinct, but given the virus in its system,  and Finch being busy with Root, was unable to act effectively. It DID save Carter’s life, but now she’s in serious trouble.

Everything comes to a head as Finch leads Root to the payphone the Machine will call. Finch pulls some kind of trickery that hasn’t been explained yet, and somehow sends the call to Reese. Here’s the thing: Root also answers, and seems quite pleased with the result. I’m not sure what Finch did, but he didn’t seem worried about Root’s pleasure at having finally spoken to the machine.

The call Reese receives is delivered by a composite of different men saying “Can you hear me?”, ending the episode. From next week’s preview, it sounds as though Root receives the same message, only spoken in a female voice. Is this a result of whatever Finch did? Has the machine split into two personalities? Is CBS’ marketing department trolling us? Who knows, but I can’t wait for next week’s season finale to find out!