The first 26 years of life haven't gone so swimmingly for Moll Huntford (Jessie Buckley), a ginger-haired resident of the British island of Jersey, and the 27th doesn't look much better. Her mother, Hilary (Geraldine James), has thrown her a birthday party, though whether it's really for her is up for some debate.
After a quick toast to the birthday girl, Moll's sister, Polly (Shannon Tarbet), announces to all the guests that she and her fiancé are expecting twins, at which point Hilary orders Moll to go fetch a bottle of champagne from the garage.
Moll, played by Buckley with an astonishing mix of fragility and ferocity, does not go fetch a bottle of champagne from the garage. Instead she storms into the kitchen, breaks a glass and squeezes the shards until her hand bleeds. Then she runs off, fleeing into the night, away from a family that has never understood her and a home that can feel as stifling as a prison.
Being slighted at one's own party may seem a rather flimsy reason for self-mutilation and abandonment. But one of the virtues of "Beast," a tense and atmospheric thriller written and directed by Michael Pearce, is its acute sensitivity to the painfully exposed nerve endings that no one but the sufferer notices.
Moll, who works as a local bus-tour guide and still lives at home with her mother and ailing father (Tim Woodward), has a troubled psychological history that shapes her every waking moment. No one will let her forget she's damaged goods — not her mother or her brother, Clifford (Trystan Gravelle), who sneers at her in part to compensate for his own thoroughgoing mediocrity.
All this makes Moll uniquely susceptible to the roguish charms of Pascal Renouf (Johnny Flynn), a scruffy bloke who first greets Moll with a rifle in hand and a few freshly slaughtered rabbits in his truck. Pascal is a poacher, a handyman and, for Moll, a madly attractive potential lover. Of course, Pascal could also be the serial killer who's been strangling young women on the island and leaving their corpses out in the open, but why let that remote possibility spoil a good thing?
Pascal doesn't need to be a murderer, however, to utterly horrify Moll's mother and siblings; it's bad enough that he tracks mud on the carpet and wears jeans to a fancy country-club function. Flynn gives Pascal a reckless impudence, all but reveling in his status as the ne'er-do-well boyfriend. He doesn't suit the Huntfords' ideal of upper-middle-class propriety, and worse, he makes it all too clear that Moll doesn't either.
If "Beast" were nothing more than a superbly acted misfit romance, it would be enough. Buckley, an Irish actress who recently appeared in the BBC miniseries adaptation of "War & Peace," is a startling talent, with the kind of face that can beam with uplift one minute and disintegrate into anguish the next. She and Flynn achieve such an instinctive, dangerous chemistry that you could imagine the movie working just as well — perhaps even slightly better — without a serial killer plugging away in the background.
When the police target Pascal as a suspect, the intrigue kicks up a notch, introducing a familiar but effective conundrum in which Moll is both repulsed and aroused by the possibility of her lover's guilt. (One development that's too belabored to pay off: The investigating officer is a man who's previously shown a romantic interest in her.) Making matters worse, Moll seems to be experiencing her own form of psychic rupture, as seen in a few under-the-skin dream sequences that are good for a few schlocky jolts. Before long her own dubious traumas begin to surface, in ways that begin to make even Hilary's domineering behavior seem justified.
Pearce, in his feature directing debut, proves himself a solid craftsman, with a gift for giving even derivative story elements a nerve-jangling tweak. He also has a shivery way with ambiguity, a knack for toying with our expectations and turning the power of suggestion to his advantage.
The degree to which he succeeds in keeping the killer's identity a secret is impressive, even if he has trouble sustaining believability through the story's harrowing, over-plotted final stretch. In surrendering too readily to procedural clichés, this "Beast" ultimately loosens its grip and can't help but lose some of its beauty.
Rating: R, for disturbing violent content, language and some sexuality
Running time: 1 hour, 46 minutes
Playing: Arclight Cinemas, Hollywood; the Landmark, West Los Angeles