Heretic was not the film I expected. Judging by the trailers, I fully expected this would be a medium-rate slasher flick about two young Mormon missionary girls making their way through a killer’s deadly house.

And yes, there’s a creepy house. But Heretic is the farthest thing from medium-rate, and it doesn’t draw its suspense from jump scares or gore: it’s possibly the most cerebral thriller I’ve ever seen in wide release. It’s religiously-minded horror that, for once, actually takes religion as such with utter seriousness.

While serving a mission, Sister Barnes (Sophie Thatcher) and Sister Paxton (Chloe East) stop by a lonely house, following up on a prospective convert’s expressed interest. They’re welcomed inside by Mr. Reed (a magnetic Hugh Grant), who wastes no time before engaging them in an apologetic debate over historical polygamy and the possibility of continuing revelation.

Sisters Barnes and Paxton soon learn that Reed isn’t all that interested in converting to Mormonism. Instead, he’s more concerned with converting them—to that which he cryptically describes as “the one true faith.” Their visit to his house is merely the start of a great game to be played throughout the labyrinthine structure—a game designed to radically revise their own beliefs.

Yes, this is a suspense movie. Yes, the girls are trying to escape the villain’s lair. There’s some gore—though it’s fleeting—and plenty of pervasive menace throughout. But in general, those squeamish about “horror movies” should consider giving Heretic a try. 

For one thing, Sisters Barnes and Paxton are never allowed to be the caricatures one anticipates. Early on, both girls—especially Paxton—come off as seriously naïve, with Paxton being positively overeager. Her dialogue is filled with clumsy substitutes for swearwords, and her attempts at apologetics are cringeworthy. Conversely, Barnes seems a bit more worldly, urbane—possibly on the verge of religious deconstruction herself. And yet both girls, when pushed to their limits, outdo themselves. Barnes reveals a deep faith of her own beneath her seemingly hardened, cynical exterior—and Paxton an unforeseen cleverness.

What truly sets Heretic apart, though, is the sheer length of time it allows its religious debates to unfold. These, not any onscreen violence or shock, are the real centerpieces of the film.

Reed is something of a syncretist, viewing all religious traditions as more-or-less derivative iterations of a primordial original. For Reed, surely the thematic similarities across diverse mythological and religious traditions—death, rebirth, baptism, miracles—render questionable any particular religion’s claim to be the one true faith. (This is, of course, James G. Frazer’s argument in The Golden Bough—but Hugh Grant is a bit more charming about delivering it.)

But surely there’s something beneath it all—isn’t there?

(Some spoilers follow)

It ultimately becomes clear that for Reed, religion everywhere and always is reducible to the brute fact of control. Reed’s stance isn’t quite New Atheism at its most overheated: it’s more like perennialism-turned-Foucauldian. Control surely exists, even if the divine as such does not, and control can be exerted by anyone rather than rationalized away in a haze of scientistic abstractions. To enter Reed’s house, becoming subject to his manipulations, is—for Reed—a model of all religious commitments.

Framed as it is onscreen, this claim presents a true challenge to traditional belief. Heretic, disappointingly, never really answers it. In the end, confronted with the full weight of Reed’s genealogical critique, Heretic’s “final girl” falls back on a sort of sociological agnosticism—conceding that even if prayer doesn’t actually work, it’s still a “nice thing to do.”

This is a sop to modern sentimentalism, a painfully missed opportunity to rebut Reed on his own turf. There are lots of ways to exert control, after all—but not all of them take on a common symbolic form. Smartphones are structures of control. The truly salient question is not why do these systems of control exist, but why have so many similar systems survived and converged, while others have failed? What if reality’s final truth is, in the end, baptism and death and resurrection? What if this is the deep insight that so many of the world’s great religions have asymptotically approached?

As thin as this conclusion might be, it doesn’t change the fact that Heretic is more than worth your time. This is the rare film about religion that actually feels like it was made by someone with more than a passing understanding of theology. And in the context of a thriller flick like this, that’s some of the highest praise I can give.