There’s an unmistakable vibe of The Twilight Zone to Zal Batmanglij’s The Sound of My Voice. Like Rod Serling before him, the first-time director uses flourishes of the fantastic to disguise his true subject. In the best Zone episodes, the science-fiction elements took a backseat to broad explorations of human nature. Voice does a similar thing with the story of two undercover journalists infiltrating a cult in Los Angeles.

Peter (Christopher Denham) and his girlfriend Lorna (Nicole Vicius) are would-be documentary filmmakers who contact the members of a very secretive and very obscure sect in order to get video footage of the group’s internal workings. In the film’s opening scenes, we witness them going through preparation; showers used to discard excess skin and germs, blindfolds for a clandestine van ride, and odd, symbolic greetings employed to distinguish the faithful from the outsiders.

Once inside, the arcane allure vanishes. Peter—who later swallows a transmitter so the camera in his glasses will record images and sound—finds the cult to be shabbier than he expected. A handful of baleful yuppies sit on a dingy berber carpet, dressed in loose-fitting white tunics worthy of a Vulcan, waiting on the frail, and enigmatic figure of their obsession. This figure is Maggie, a young twenty-something waif who has strange tattoos, carries an oxygen tank, and makes the bold claim that she comes from our future, a future ravaged by war and disease.

Brit Marling is an interesting and beguiling new presence in the film world. Last year, Fox Searchlight introduced her to the world in the sci-fi drama Another Earth, which she also co-wrote. There she played the shy, beautiful and damaged Rhoda, who dreamed of traveling to another planet in hopes of finding a life untouched by tragedy. Ironically, Maggie’s back-story isn’t that dissimilar; if she’s telling the truth, she’s escaped a dark, meager existence to seek sanctuary in the past and find those she remembers loving in the future. The trick of course is that we don’t really trust Maggie, Peter doesn’t want to trust her, and although Lorna yearns to believe her, she’s not made the same leap the others have.

But then, Marling starts working her magic, presenting icy, determined calculation and naïve frailty in the same vessel, turning each on and off while suggesting that it is Maggie, not herself, managing this part of the performance. Even Peter, driven because his mother succumbed to illness due to a cult’s influence, is having a hard time seeing around his own hypocrisy when she starts making eyes his way. With her long, fairy-tale tresses and meek doe eyes, off-set by a delicately lovely half-smile, Marling suggests more a dazed, navel-gazing Starbucks barista than the powerful, hypnotic leader capable of inspiring her followers not just to worship, but bodily sacrifice. Members of the group give willing blood transfusions to sustain Maggie’s allegedly failing immune system and something in Marling’s canny transitions make us believe that she could indeed spur them to such fealty. She is the lifeblood of Voice and she imagines Maggie so completely that this narcissistic and enigmatic contradiction becomes one of the year’s best characters. Denham and Vicius are also good, but tune themselves into Marling’s wavelength, becoming more offshoots of that character’s conflicting facets than individual agents of their own.

Unlike last year’s Martha Marcy May Marlene, which also took a look at the power of cults and their effect on those looking for meaning,Voice has more to offer than just a surface exploration. In the male oriented commune of MMMM, it was virility and sexual subjugation that necessitated the cult’s existence and it was divisive, deceptive promises that kept it running. Here, there is no commune, no barrier, and no prison save for the one of doubt and dread that Maggie has instilled deep within her followers. She and they probably don’t see it that way though. Instead they interpret Maggie’s suffocating control, emotional bullying, and eviscerating honesty as signs of love, solidarity and supernatural wisdom. Maggie’s ‘family’ is not a living arrangement but a series of weekly gatherings  that allow followers to retain their sense of free-will while treating Maggie and her methods as something more socially harmless; either personalized religion or edifying New-age therapy. A third act set-up actually goes further still, as Maggie deliberately steps into the mold of the biblical Christ, complete with the most repellent last supper. A riveting question is proposed. Even if she is who she says is, does it justify her actions and behavior with these people?

Batmanglij and Marling understand the divisiveness of the very pointed questions they are asking, and the challenging task they put to the audience; to really understand the headspace, it requires the viewer to ultimately experience the same jilting as Maggie’s followers. For most of the running time, Batmanglij keeps the proceedings grounded in the mundane, drained of transcendence and centered almost completely on the battle of wills and ideologies occurring between Peter and Maggie. The gathering plot threads—what would be considered the hook of a Twilight Zone episode—hint at a larger, building structure we never fully see. There are curious images. A middle-aged business woman  painstakingly searches a hotel room for wiretaps and contraband.  One of Peter’s students is targeted by Maggie as being special and there are scenes of her sitting in her bedroom constructing ravaged metropolises with building blocks. In some shots her father stands behind her, a man with a worrying gaze and ominous needles. We haven’t been given the full story but have enough snapshots to create a reasonable portrait.When the final sequence comes, it is these genre-friendly elements of the narrative that leap into focus.

The power in The Sound of My Voice lies with Marling whose performance is also a complex commentary on the leaders of thought-controlling sects. We don’t see her as a freak or as a particularly monstrous individual, and at several junctures we are tempted with her fantastical promises. Behind her eyes and the final, engrossing frames of the film, exist a simple but often overlooked truth; faith is hardest not when it relies upon a thin lie but when it is backed by the threat of substantiated reality.

Here’s a truth to hold on to; Brit Marling is the real deal, and if she keeps producing work this compelling and engrossing, she’s going to have a cult all her own.