The question of protagonist Kevin Garvey’s sanity was first raised in the pilot, wherein he may or may not have fired his gun at a pack of wild dogs. The second episode “Penguin One, Us Zero” seemed to look on uncaringly as poor Kevin lost his shit over a disappeared bagel. Since then he’s inexplicably lost track of a closet full of white shirts, tethered a dog to his fence without any recollection of doing so, and crusaded across Mapleton to find a stolen baby Jesus doll. After all of that it’s still not exactly clear what’s eating Kevin Garvey, nor is it even clear whether he is or is not crazy. Moreover, it’s not clear how Kevin losing his sanity ties in to the greater themes of The Leftovers.

“Cairo” changes all of that. Crazy is a strong word, but Kevin’s definitely not A-OK upstairs. Clear is a strong word, too, so perhaps we should state that the clarity we get on Kevin’s mental state and how that mental state ties into the grander schemes of the series isn’t exactly a straightforward answer. But Kevin’s sleepwalking comes with serious bouts of amnesia, and he often wakes up to find he’s done something questionable — like tying a dog up in the yard — during his waking slumber. In “Cairo”, he gets downright violent, so much so that the part of himself that he never remembers becomes something that he doesn’t want to be a part of himself at all.

The Jekyll/Hyde contrast takes an extra step in two different directions. First, Kevin’s Jekyll has no knowledge at all of Kevin’s Hyde, at least not going in to “Cairo”. The dog, the white shirts — all of that gets explained away or just falls by the wayside. But when Kevin wakes up in the first of Cairo, New York, and realizes he’s tied the Guilty Remnant’s Patti to a chair and beaten her overnight, Hyde becomes all too real. He’s still deniable, though, at least as far as Kevin is concerned, and so he resists the idea that he’s played any part in the violent abduction.

The second, higher level is the relation to the Departed of The Leftovers, the percentage of people who simply vanished into nothingness. The Hyde part of Kevin seems to have done the same, wiped from all memory and seemingly nowhere to be found. Again, though, this is only so far as Kevin is concerned — to everyone else, the danger and Kevin are one and the same. Either way, the Departed still have a sizable effect on the world in the same way that the departed part of Kevin does, causing havoc and then receding into nothingness.

Patti and Dean, the other two significant characters in “Cairo”, speak to this thematic parallel in different ways. Patti describes Dean as “a ghost”, and indeed it seems Dean has a particular kinship with the ghostly part of Kevin and an antagonistic relationship with the “real” Kevin. “Most people you can find out all sorts of things about them with no trouble at all,” Patti says to Kevin of his accomplice. “But you, dog-killer…no driver’s license, no records. No anything. So I don’t know if you can shed some light about our friend here? Because as far as I can tell, he’s a ghost.” When Dean leaves the cabin he mutters “I tried”, which seems to be directed at the room in general. And yet Kevin’s father, who may or may not have some communion with the Departed, often says the exact same thing. Thus does Dean’s muttering provide another parallel, one wherein Dean is a returned member of the Departed or one only visible to other Departed beings.

He’s at the very least aware of the dichotomy in Kevin, despite his learning about it in this episode. He describes the Kevin that abducted Patti as a “leader”, and tells the Kevin in front of him that “the man currently residing in his skin clearly has no idea what is happening in there.” Feebly, Kevin says he doesn’t want to hurt her. “Oh yes you do,” says Dean. “You could only get so far because you are a good man…I need to talk to the other guy.” If we’re following the train of thought here, the possibility exists that the Departed are not, in fact, in a better place somewhere (this question was raised explicitly by Nora in “Guest“). For Kevin, finding the Departed (in himself) is something to be resisted, something terrifying, something inevitable.

And yet “Cairo” also presents that unknowable part of yourself as a true escape, a sentiment which any Hyde would agree with and any Jekyll would be terrified by: it’s Hyde who’s the real human laid bare and Jekyll that’s the facade. Patti describes the reasoning behind the G.R.’s spartan lifestyle and white clothes and bare walls, their bare lives. “We strip ourselves…until we are erased. Blank slates.” That’s how the G.R. remembers the Departed, and how they serve as living reminders to everyone else. The sleepwalking version of Kevin is a blank slate, erased as soon as Kevin wakes up but free to do anything until then. It’s another thing that Kevin is forced to confront in himself: the reminder of the Departed.

“Cairo” frames Kevin’s condition over grief, over remembrance, over many things, but mostly it raises the question of true understanding. Kevin can’t even grasp his ostensible self, much less the inexplicable event that wiped entire families form the face of the earth. As The Leftovers marches toward the finale of the first season and as the second season looms on the horizon, “Cairo” will likely stand as one of the most important episodes of the series.