OK, the patriarchal thing is weird: The young women prepare the meals, laying out the table for the men to eat. Afterward, the women clean up, and then sit down for their food. In silence.

But at first glance, there's something idyllic, in a retro-hippie, back-to-the-earth way, about the group of people living and working on a big farm in an isolated corner of the Catskills. And the man presiding over this commune - older than the rest, with craggy features and a guitar he pulls out to concertize his flock - well, they adore him.

Of course, this Patrick (a modulated and creepy turn from John Hawkes) belongs in a gallery next to names like Manson, Jones, Koresh. But one of the remarkable things about Martha Marcy May Marlene, a first film from the preternaturally accomplished Sean Durkin, is that the word cult is never uttered - the truly dark and disturbing goings-on on Patrick's farm are presented in a low-key, naturalistic style that makes the narrative all the more unnerving.

Martha Marcy May Marlene is the story of a scarred, scared woman - an extraordinary, mesmerizing performance from Elizabeth Olsen - who escapes from this place, and seeks shelter, and support, in the lakeside country house of her older sister (Sarah Paulson) and brother-in-law (Hugh Dancy). But Martha, as the title of Durkin's beautifully spooky film suggests, no longer knows who she is - her sense of self is gone, her hold on reality tenuous at best.

Something happened during her time in the mountains. Something bad.

Martha Marcy May Marlene moves from its protagonist's dream state to her memories to her waking present in imperceptible shifts - the effect is disorienting, at first, but ingenious. We're as rattled and wary as Martha is - we're seeing the world as she does, pulled under in the wake of her trauma.

Durkin has clearly studied some masters of the subjective eye - Polanski (Rosemary's Baby, Repulsion) and Haneke (Cache, Code Unknown). He knows how to use the camera (and sound - the sound in this film is amazing) to evoke paranoia and a profound sense of confusion. But he has also found an actress, Olsen, who is every bit as adept: She's like a quiet force-field of shattered nerves, with deeply haunted eyes, with gestures, small and controlled, that convey big, wild emotions.

Olsen inhabits Martha's broken world completely. And at the movie's end - a jarring, boldly ambiguous end - we're in her head, too, not sure what is real, and what is not.EndText

Contact movie critic Steven Rea at 215-854-5629 or srea@phillynews.com. Read his blog, "On Movies Online," at http://www.philly.com/philly/blogs/onmovies/