Hugh Grant turns his natural charm into a weapon in “Heretic,” a stimulating discussion of religion that emerges from a horror movie wrapper.

That’s the premise, and the 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 from Chung Chung-hoon (2017’s “It”),