Time is out of joint in "Martha Marcy May Marlene." Sean Durkin's compulsively watchable first film is a psychological thriller camouflaged as an Ingmar Bergman-style country-house drama.

The film opens with scenes of fresh-faced Martha sneaking away from a communal farm in rural New York. She takes refuge in her sister Lucy's oversize Connecticut lake getaway, sharing nothing about her absence the previous two years. The past won't stay buried, though, and the seductively edited film drifts back to her troubling memories. It's a modern variation on the Caligari motif, the world as it appears through a mad person's eyes, and it's alarming. Anxiety cascades through the richly atmospheric story in a chilling flow.

As Martha, Elizabeth Olsen makes a remarkable debut, by turns showy and subtle. Womanly, but with a touch of baby fat in her cheeks, she looks easily bruised. Just as you begin worrying for her, she turns sharp and aggressive.

Lucy (Sarah Paulson, in an emotionally detailed performance) feels responsible. With their mother dead, she's the only adult in Martha's life. But she doesn't know how to deal with her little sister's erratic behavior. Martha flaunts some confrontational nudity in front of Lucy's new husband Ted (Hugh Dancy), a persnickety English architect. She pitches a fit when a scruffy, friendly bartender at a cocktail party reminds her of the manipulating hippies from the commune who undermined her identity. Just when Lucy and Ted are set to pitch her out, Martha collapses, and they nurse her through the night.

While her unpredictable actions make her difficult to warm to, Olsen's delicately shaded performance stirs a contradictory protective impulse. Durkin draws us in to identify with her hallucinations by muddling our own emotions. The shots are carefully designed to remove markers of time and space. From cut to cut we can't be certain whether Martha is in her sister's opulent home or the ramshackle farm house, whether she's recalling the past or being stalked in the present by a member of the polygamous cult.

John Hawkes plays Patrick, the shrewd cult leader, a bookish, mellow-voiced father figure who blends overtones of a self-esteem guru and Charles Manson. In a handful of skillful scenes he creates a presence that drips poison into every subsequent frame of the film. Yet we understand that in its own way the Lucy and Ted relationship is toxic and sterile.

The aim of the movie is to put us deep in the unsettled mindset of a woman experiencing post-traumatic stress, and it goes about the task with talent and originality. The ending, a bravura anticlimax, will be emotionally upsetting for some viewers, but I felt it was inspired. Closure is for wimps.