The first feature film from young writer/director Sean Durkin is certainly a stylistically assured debut — mysterious, moody, unbearably tense in parts — but all the style can't shroud the fact that there isn't much substance.

If you, like New York Magazine, are deeply concerned about the fate of listless, unemployed young women from seemingly upwardly mobile families in these troubled economic times, Martha Marcy May Marlene offers one extreme possibility: Those aimless young things could join a creepy cult in upstate New York and live communally on a farm and.. well, I won't tell you the rest. Oh, I kid. Those tiny wanderers will be just fine without mountain cults. Which, as Martha Marcy May Marlene shows in vague detail, are pretty scary groups, even if they are populated by attractive boys and girls in loose dresses and Hanes tank tops.

This is the setting for half of this, for lack of less hackneyed phrase, "psychological thriller" — though the word cult is never used, there is something immediately unsettling and cult-like about the shabby-pretty Catskills commune run by a witchy-looking older man named Patrick (John Hawkes) and staffed by a bevy of braless young women and a few sullenly handsome young men. There's a mysterious thickness in the air, a heaviness to Hawkes' quiet purr, that our hero Martha (Elizabeth Olsen) initially mistakes for comfort and emotional warmth. But we the audience know there's something off about it, likely because the film opens with a scene of Olsen fleeing this place and tearfully, with not a little fear in her voice, begging for her sister Sarah (Sarah Paulson) to come get her and take her away.

The tony Connecticut summer home rented by Sarah and her husband Ted (Hugh Dancy) that the rescued Martha is taken to provides the present setting for the movie, while flashbacks to Martha (renamed Marcy May by Patrick) venturing down the farm's dim rabbit hole are woven throughout. In Connecticut, there is something off, broken, odd about Martha, but as she seems interested only in sleeping and providing monosyllabic answers to their questions, Sarah and Ted remain clueless as to what has happened in the two years since the sisters have seen one another. And so the movie unfolds, chronicling the immediate paranoid days after Martha's flight and the increasingly grim time (weeks? months? two years?) Marcy May spent in the thrall of Patrick and his addled harem. Moments in the present bleed seamlessly into memories, or are they dreams, of the past and Martha becomes increasingly unraveled.

It's hard to talk about this movie without revealing the various details that make it so tinglingly suspenseful, but know that there is a kind of mundane, almost gentle horror at work on Patrick's compound that lends it a shiveringly chilly air of believability. One could easily imagine a real-life damaged young woman like this — seemingly orphaned, estranged from her sister, lost — accepting one thing after another, bartering parts of herself away again and again in exchange for the (false, perhaps) sense of family and community she gets in return. It's the low-to-the-ground, unflashy depiction of this kind of mental cataclysm that gives Durkin's film its nerve-rattling engine. It's rare in film to see terror presented so delicately and without sensationalism — Durkin's camera hovers and wanders and searches, a series of lovely brushstrokes that, when he finally pulls back, turn out to have created something terrible. It's a treatment that renders the danger and depravity as everyday as tilling a garden or chopping wood, thus making it all the scarier.

That is the good work of this film, and while it's a style and technique that sustains it near about through to the end, on closer inspection all the shadow and mist of foreboding and creepiness seems a bit of a nifty trick and little else. Ultimately there is so little actual meat, and such a crutch-like reliance on ambiguity in the film, that I can't help but suspect that Durkin came up with an alluring concept and a striking aesthetic in which to present it and got so excited that he entirely forgot about important, less exciting things like character and motivation. Paulson and Dancy's characters are reduced to flat stereotypes — affluent bourgie types who are kind and welcoming until Martha starts disrupting their moneyed idyll. It's a trope we've seen many times before, and here Durkin offers us no new insights or variations on these stock characters. Sarah is rigid and fastidious, Ted is just trying to unwind from his busy job. That they are so square is maybe deliberate, a way to starkly contrast the loosey-goosey hippie people of the farm, but even if that's the case it's still such an obvious device. In one scene, Martha questions Sarah and Ted's empty materialism over dinner, and while the forcefulness of her argument is telling in its rote, dog-trained quality, the bones of the conflict feel so well-worn, so stagey that it sucks the cool believability that the film feeds on right out of the scene.

And as to that overly abundant reliance on ambiguity, we never learn the chief why of the matter, specifically why Martha ever ended up at this awful farm in the first place. We get wispy snippets of family backstory, but they're just not enough. If Sarah and Ted are boring white stick figures, Martha is nothing more than a cipher. Olsen is a commandingly lovely actress, with soulful eyes and a gracious figure that, if only compared to her scarecrow sisters, one could almost call zaftig. (In truth she's just got hips, that's all.) And she has moments of true potency in the film, as Martha's fears that she hasn't gotten far enough away begin to mount. (Durkin depicts the growing dread in haunted house movie style — it's terrifically unnerving.) But the bulk of her time in the film is spent staring and blinking, wordlessly reacting to the clamor around her, or lying on beds with those big cow eyes open and glazed over. She's supposed to be searching for something in these scenes, and at times I bought it (muted and shellshocked makes sense for the post-cult world, but in the flashbacks it would have been nice to see a little more exuberance, a little more want that might explain why, or at least how, this intelligent woman got caught up in this mess), but there are moments where all of this mooning seems to go from placid depiction of a character's inner confusion to Durkin just wanting to let his camera explore the contours of this beautiful young actress. And that feels deeply unfair, almost cruel, in a movie that is, partly, about sexual objectification.

Martha/Marcy May's (I'll leave you to find out who Marlene is) silent stare routine is straight out of the current indie playbook — you could do a parody mashup of her and Ryan Gosling in Drive wordlessly staring at one another for hours — and while much of this film is inventive and dexterous and gorgeously unsettling, I think it falls prey to a lot of those indie trappings. All of the cannily composed shots and narrative wandering in the world can't completely compensate for a lack of emotional sincerity, which is where the film ultimately flounders. I left the theater certainly feeling jangled and ill at ease, but I wasn't moved by anyone's plight, was not educated in any way in the emotional mechanics of cults or victimhood or crisis recovery. Durkin tells a moody story about something that bears a lot of psychological inspection, but we do not get that here. Like the lake that is used as something of a visual metaphor throughout the movie (lake as mystery, lake as the fluidity of memory), Martha Marcy May Marlene is dark and looming and picturesque. But I'm afraid that when you put a toe in, you realize it's only puddle deep.