Spooky season may be over, but the holidays are upon us — this is the time when billions come together to celebrate cherished traditions and sacred histories.

So, the latest horror film from Bryan Woods and Scott Beck is still relevant, because in “Heretic” the question is asked: What if all that communion and ritual is hogwash?

The setup is simple: Two LDS missionaries (Sophie Thatcher and Chloe East) arrive at the house of a potential convert (Hugh Grant) just as a blizzard begins to hit.

However, the real storm starts with Grant’s first question: Why believe in *this* particular faith? As the inquiries get more pointed, the camerawork gets more intense, and an eeriness settles in to stay.

The heart of the film resides in the heart of the house — a library host to many conflicting ideas and two potential exits.

It’s here where both Grant and the audience have the most fun, as monologues twist and stomachs turn. Thatcher plays frightened hilariously (the whole film has a surprising amount of humor), and East is wonderful in her hesitant steadfastness.

It would’ve been lovely if the film had simply stayed in this room, with the three sparring back and forth about the origins of faith, why people believe, and the modern-day functions of religious structures. The stakes are there because not only is physical safety on the line, but all of eternity, and the tension is there because it all hinges on a simple decision: Belief or disbelief?

Unfortunately, Woods and Beck can’t help tilting into full-on horror territory for the second half of the film, where the craft remains just as clever but the plot’s revelations are increasingly unengaging. Grant’s ultimate thesis is disappointingly simple for a supposed scholar of religion, and maybe that’s the point — one is nonetheless a tad underwhelmed after so much buildup by the filmmakers.

Which is not to say the enterprise is unsuccessful — the final product is a thoroughly effective can of thrills, with the editing in particular being top notch. However, the eventual near-abandonment of its theological charms for a tale of simple survival (along with a few stray lines that leave a sour, anti-intellectual taste in one’s mouth) make for a film that likely won’t elicit further enlightenment on a rewatch.