IMMACULATE

R, 89 minutes. Waterford, Westbrook, Lisbon.

Blood-soaked and candlelit, Michael Mohan’s “Immaculate” disabuses the notion that any conception is ever without sin. Starring Sydney Sweeney (who also produced the film), this cheeky, freaky, lushly designed horror movie presents as a giallo nunsploitation riff, but the script, by Andrew Lobel, is much more “Rosemary’s Baby” than it is “The Devils.” Still, Mohan wants “Immaculate” to be an exploitation flick, and so it is an exploitation flick, which means he has adorned Lobel’s script in texture, atmosphere and viscera, taking the genre seriously while also applying an ironic wit. He skews toward modern horror filmmaking, but has the references and deep film knowledge to make “Immaculate” feel more like a long-lost video nasty dredged up out of an obscure archive. Sweeney stars as Sister Cecilia, a doe-eyed and docile devotee from Detroit who has traveled to Italy at the behest of a Father Tedeschi (Álvaro Morte) to take her vows at a secluded convent where she will care for elderly nuns. Soon, shockingly, she’s exhibiting pregnancy symptoms, her womb thrumming with a whooshing heartbeat under a sonogram machine. Her spontaneous conception is seen as a miracle, the resurrection of God. She has no choice but to carry this pregnancy to term, surrounded by jealous novitiates, senile nuns, controlling male leadership and a secret sect of the sisterhood who wear crimson shrouds over their faces. It’s something of a wonder to watch Sweeney as she undertakes Sister Cecilia’s journey, transforming from a meek naif into something unexpected and wild, her pious discipline falling away with every indignity. As this swift, 89-minute film builds to an absolutely feral climax, we do believe her, perhaps most of all in the film’s final, jaw-dropping moments, as she embodies a pure animal honesty.