After a big twist, FOX's The Exorcist's demonic presence is revealed, as the series moves from a haunted house story into something much worse.

If you haven’t been following season 2 of FOX’s The Exorcist, now would be a great time to jump on board. So far this season, the series has delivered a taut hunted house mystery over the course of its first four episodes, making the foster home run by John Cho's Andy into an appropriately, though uncharacteristically, sinister abode, teasing a malevolent presence in the home infecting not only the kids who live there but also the environment around it as well. After the show delivered a terrifying episode last week with 'One For Sorrow' that will have you concerned there's a shadowy presence at the foot of your bed, the hour ended with a big reveal that one of the children is not what she appears to be – in that she's not really there at all.

The twist that adorable agoraphobic Grace (Amélie Eve) exists in Andy's mind as part of the evil corrupting the secluded Pacific Northwest island is reminiscent of the twist in season 1 that disclosed Geena Davis' Angela Rance was in fact Regan from the original film. The Grace reveal may not have the same impact as the one tying FOX's way-better-than-anyone-could-have-guessed series to William Friedkin's 1973 feature film, but it does deliver a turning point of sorts for a season that has been largely invested in the atmosphere of things. That investment began to pay off with the realization that Andy, the one guy who seemed to have things together despite considerable odds against him – his wife died recently and he's running a foster home all by himself that's currently being scrutinized by an ex-girlfriend he seems to still have feelings for – isn't as solid as we'd like to think.

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Cho has been so good in slowly revealing the cracks in Andy's patient, fatherly veneer that following Verity's (Brianna Hildebrand) discovery that Grace's upstairs bedroom is really a derelict shrine to the late Nicole Kim (Alicia Witt), it will be worth it to take a second look at the first four episodes to see just when and where Cho and the series Shyamalan'd everyone watching. But as it was with season 1, there has to be more to a twist like this than the mere shock of discovering how far back the story goes or having been misled into thinking a little girl whose coping mechanism is a putting a creepy pillowcase over her head is real. While the writers had the benefit of 40-plus years of fandom (and some not-so-great sequels) to play with previously, here they're left largely to their own devices, and the results are somehow even more unsettling.

Amelie Eve in The Exorcist Season 2

Perhaps it feels so unsettling because the show is entering into unknown territory, and after watching what was believed to be one of the more reliable characters give over to an increasingly agitated and panicked state, it feels like The Exorcist could be taking its audience anywhere. That's a relief, as even though the early part of the season thought up some visually compelling ways to make Father Thomas and Marcus' cross-country pursuit of demons and the eventual exorcism of them more interesting than simply filming two guys yelling at some poor pea soup-encrusted soul on a table or bed, there was a creeping feeling that we'd been there before.

The excuse for keeping Marcus and Thomas on the island has also been stretched about as far as it can go. Sure, if two guys are going to sense an evil presence and feel compelled (by the power of Christ, naturally) to seek it out and possibly send it back to hell, then it's these two, but Thomas can only swing by Andy's house to check on Harper (Beatrice Kitsos) so many times before the audience starts looking at him with the same resignation as Verity does when she opens the door. So, to that end, 'There But For the Grace of God, Go I' manages to bring a renewed sense of purpose and urgency to the proceedings, one that happens to justify the chilling slow-burn pace of the season so far.

Alex Barima Cyrus Arnold and Jon Cho

Thankfully, there's more to the hour than just the well executed follow through of last week's reveal. In between Andy's ill-advised impromptu camping trip and the realization that what's haunting him isn't confined to the house he tried to leave behind, the hour finds time to offer a few well-earned grace notes for two its characters: Verity, who confides in Shelby about her experience being a young gay woman assaulted in a very nasty way by religious intolerance, and again with Marcus making a meaningful connection with Peter Morrow (Christopher Cousins), after his reluctance to do something similar last season.

Moments like those help ground the series with an important emotional context, and it's no surprise that they are given such prominence here as The Exorcist is set to turn up the heat and go full-in on its supernatural elements. A lot of that will fall on Alicia Witt's performance as Nicole (but totally not Nicole), which has been a greatly appreciated foregone conclusion since the season premiere. It's much better for Grace to have played the unexpected element this season rather than Andy's wife, and although they both seem to be the product of the same family-killing demon, Nicole's inclusion looks poised to bring this series to an even creepier place.

Next: The Exorcist Serves Up More Solid Demonic Scares in Season 2

The Exorcist continues next Friday with 'Darling Nikki' @9pm on FOX.