Grade: C+

On the most mundane level one could say that “Martha Marcy May Marlene” is a movie about a young girl who escapes a cult and has trouble readjusting to the outside world. But that makes it sound like the sort of thing you might encounter on the Lifetime Network, and it’s far from that. The picture has been described as a psychological thriller, but that’s misleading. It certainly aims to be emotionally unsettling, and it contains a few shocking moments. But it’s essentially a somber, tense character study that relies more on suggestion than explicit point-making, so that a viewer has to try to fill in narrative gaps himself. And it closes so obliquely that it doesn’t so much end as simply stop. It’s a film that’s bound to elicit disparate reactions, from ecstatic acceptance to curt dismissal.

One element that’s unarguable, though, is that Elizabeth Olsen—yes, one of those Olsens—gives a strong performance, nuanced in the title role, that of the girl who essentially changes identity as she goes through the stages of her unhappy life. Her given name was Martha, but after what must have been a difficult childhood she was recruited into a rustic family-like community in upstate New York headed by a quietly charismatic fellow named Patrick (John Hawkes), who calls her Marcy May. (We’re not given any specific information about what occurred in her early life to explain her turn to this cult. Apparently her parents are dead, and later it’s shown that she’s been estranged from her older sister. But details aren’t provided.)

Marcy May’s new “family” is a place where the women occupy a subservient place (they all prepare food for the men and then eat after them, and sleep on mattresses strewn on the floor of a single room). And along with the other men they’re in the thrall of Patrick, but also have a special role to play—each of them is at some point taken, drugged, to the leader’s bed to have sex with him. And all the women use the name “Marlene” when answering the phone.

What passes for a plot begins when Martha suddenly decides to leave the cult and runs into the woods, eventually reaching town. And though Patrick’s second-in-command (Brady Corbet) follows her there and briefly accosts her, she finds the courage to call her sister Lucy (Sarah Paulson), who comes and takes her to the lakehouse she shares with her architect husband Ted (Hugh Dancy).

From this point the film concentrates on Martha’s stumbling efforts to reconnect with the ordinary world represented by Lucy and Ted, and her fear that she’s being stalked by the cult members. Unaccustomed to conventional social mores, Martha frequently acts in inappropriate ways—climbing into bed with the couple while they have sex, taking a skinny dip in the lake. And via flashback it’s revealed why she fled Patrick’s “family”—during one of the home invasions they conducted, they killed a man. Ultimately Lucy and Ted decide to take her to a facility where she might be helped, but something intervenes. What exactly it is, however, remains unclear as the film ends; and what direction Martha’s story might take from there is equally ambiguous.

Parts of “Martha Marcy May Marlene” are very effective in creating a sense of unease. It’s difficult to forget the creepy character Hawkes creates, whether he’s singing a song he composed for Martha/Marcy May or teaching her to shoot a gun. And some of the abruptly peculiar moves Martha makes toward her sister and brother-in-law are viscerally disturbing as well.

And yet although the fractured narrative style is a defensible directorial choice, mirroring Martha’s personality, with its damaged sense of identity and chaotic memories and fears, Sean Durkin, working in concert with editor Zac Stuart-Pontier, employs it in a self-conscious way, until it comes to feel artificial and forced. And the ending comes across as too clever by half.

So “Martha Marcy May Marlene,” shot by Jody Lee Lipers with a sensitivity that belies the modest budget, is a subtle, sporadically powerful portrait of a young woman in turmoil. But unfortunately its fractured, elliptical form—while defensible from a stylistic perspective—ultimately undermines its effectiveness as drama.