On a rainy afternoon in suburban Colorado, two young Mormons, Sister Paxton (Chloe East) and Sister Barnes (Sophie Thatcher), knock on the door of an isolated cabin. They are greeted by Mr. Reed, a charming Englishman who invites them to warm up and enjoy a freshly baked blueberry pie. They know they shouldn’t, but Reed is played by none other than Hugh Grant, who, at 64, still has the twinkling eyes and tousled hair that wowed Julia Roberts 25 years ago in “Notting Hill.” Who could say no?

That’s the premise and clever casting of “Heretic,” a horror film starring Grant in his least likely role: a total sicko. Written and directed by Scott Beck and Bryan Woods of “A Quiet Place,” the film features moody cinematography by Chung Chung-hoon (2017’s “It”), claustrophobic sets by production designer Phil Messina (“The Sixth Sense”) ) and solid scenes. performances from its lead actors (both of whom grew up in the Mormon church). But the star attraction is Grant, who uses the restless schoolboy persona he perfected in romantic comedies like “Love Actually” to play a role more reminiscent of “The Silence of the Lambs.”

Initially, the protégé Paxton and the more worldly Barnes simply cannot believe that their host friend is actually their captor. And despite the loudest alarm bells (the house is covered in metal, he mentions), we don’t want to believe it either. Grant’s Reed is such an expert stutterer and eyelash batter that he can make a phrase like “The front door won’t open again” seem completely harmless.

With its three characters and unique setting, “Heretic” often feels like a play and could have worked well as one. Reed’s theological monologues are wild, witty and inventive – he connects Mormonism to Islam, then to board games, then to Lana Del Rey – and his mind games can be diabolical. (By labeling two exit doors “Belief” and “Disbelief,” Reed becomes a malevolent Monty Hall.) As the plot thickens and new players enter the fray, the story becomes less compelling. The talking segments may not be terribly scary, but they’re the most fun.

If you see the film at an Alamo Drafthouse in New York, you will be bombarded by the scent of blueberries in the auditorium. It’s a nice gimmick, although what “Heretic” really needs is a stronger storyline and more scares. Still, Grant will draw you into this modest little horror film and – unlike Mr. Reed – make you glad you stayed.