A pair of Mormon missionaries (Sophie Thatcher and Chloe East) are locked in a malevolent man’s (Hugh Grant) house in this preachy horror movie they should have called The Book of Moron.

The evangelists’ faith is tested along with our patience, as Grant’s character mansplains religion to the young women in order to feel superior; a tale as old (and long) as time. Although the three-hander could work on stage, the film is like being trapped in a philosophy lecture for two hours. And not a particularly interesting one; the level of anti-religion debate is juvenile and largely irrelevant, while the character motivations make about as much sense as the Mormon doctrine.

For all its intellectual posturing, Heretic falls back on the same twists and beats as every recent horror flick from Barbarian to The Watched, spelling out its monothematic thesis in a didactic story in desperate need of some ambiguity or basic logic. Hugh Grant relishes the role, continuing his villainous spell from Paddington 2, but the only magic here is the underwear. Everything else is pants.