Like vines slowly overtaking an old house, Beast—the feature debut of writer/director Michael Pearce—mines horror from the feeling of wildness encroaching on civilization.

It’s set on the island of Jersey, a land of lush pastures surrounded by an aquamarine sea, and where authorities are searching for the culprit behind the brutal murders of several young girls. (True-crime buffs might recall that in the 1960s, the British isle was plagued by a serial rapist nicknamed the Beast of Jersey.)

But Beast isn’t really a crime procedural; it centers on Moll (Jessie Buckley), an angsty twentysomething who still lives with her parents and is tormented by flashbacks to a violent episode involving scissors.

Beast has many sources of needling tension, but the most gripping is the relationship between Moll, who’s clearly outgrown the confines of her childhood home, and her cold, authoritarian mother, who treats her daughter like a wild animal that could lash out without proper discipline.

That all changes when Moll falls in love with another outcast, the ruggedly handsome hunter Pascal (Johnny Flynn), who gives her the acceptance she’s never received from her family. (“You’re wounded,” he says when they meet. “I can fix that.”)

But when Pascal is named as a suspect in the island’s serial killings, Moll’s feverish devotion becomes a ring of fire that further isolates her.

Soundtracked by an angelic women’s choir, the film’s grotesque—but completely riveting and scarily believable—transformation from fairy tale romance to psychosexual horror is captured with striking, incongruent images, like that of dirt sullying a white couch or stuffed into Moll’s mouth.

It’s both intoxicating and claustrophobic—a swirling vortex of desire and denial that exposes the wildness behind our most controlled exteriors.