Reese and Finch are on a stakeout, when they’re joined by Carter. And since we know her to be dead – and since Person of Interest, we assume, didn’t give her the slows-your-pulse drug – this has to be a flashback. And a melancholy one: we miss Carter, even more than we miss Shaw. Meantime, in the present day, the Number is Chase Patterson, who had left the country after being accused of killing his family. Reese decides to reinvestigate, and finds out that the original investigation was one of Carter’s.
But as Reese pursues the murderer, the flashback – for reasons which will become clear – starts to turn into a hallucination, and while Reese hovers on the brink of opening up to Carter, the viewer is invited to wonder whether the conversations we’re being shown ever actually happened. Given that the end of the season isn’t far away, ‘Terra Incognita’ is a daring episode, but it more than amply repays watching: as it unwinds it becomes progressively more haunting, elegiac, and startling.
There are also hints of a gangland war between the Brotherhood and Team Elias, and this theme is brought front and centre in the next episode, ’Asylum’, which in contrast to ‘Terra Incognita’ is breathless and thrilling and throws the kitchen sink at us; just about everything which has been bubbling away during the season is brought to the boil. The Numbers are Dominic and Elias themselves, and while the death of one or the other might not be a huge loss to humankind, Reese and Finch recognise that a full-on war needs to be prevented if possible.
The Machine isn’t entirely across Elias’s activities, because rather than electronic communication he’s using the ancient pneumatic tube network around Manhattan – that again – but Reese and Fusco track him to his headquarters, warning him that The Brotherhood is coming for him, even as Dominic’s soldiers are smashing their way in. So Elias, Reese, and Fusco are captured and tortured; Dominic wants Elias to yield power, and he wants Reese and Fusco to give up Finch. Which, of course, they won’t do.
Meantime Finch himself is helping Root, who receives a phone call from a panicked Shaw. The Machine refuses to let Root know where Shaw is, so Root uses what leverage she has as one of The Machine’s assets – and only human interface – and engages in a spot of brinksmanship, successfully changing The Machine’s mind. So Finch and Root go to a psychiatric hospital which also turns out to be the Samaritan head office, and they’re captured as well. Whereupon two truly great things happen: The Machine and Samaritan go toe to toe, with The Machine ultimately sacrificing herself for her disciples. (Explicit theological metaphors again.) And Root warns Martine that if she, Martine, lays a finger on Finch she’ll be killed. Martine lays a finger on Finch.
And if that weren’t enough, Control has abducted an apparently innocent mom and teacher. Control is adamant that she’s a Samaritan agent. The mom doesn’t know what Control is talking about. Until she does. All of which means that with Dominic vs Elias, Machine vs Samaritan, and Control vs Samaritan under way, Shaw out there somewhere, Harper Rose apparently – but ambiguously? – on Dominic’s side, and Samaritan promising an event known as The Correction, we couldn’t be more nicely set up for the season finale.