Available on DVD: “Sound of My Voice”

Nobody is gutted in Sound of My Voice, a smart, effectively unsettling movie about the need to believe and the hard, cruel arts of persuasion. But over time the men and women who meet in a mysterious house in an anonymous Los Angeles neighborhood — where they shed their clothes and cleanse their bodies in a ritual — are opened up bit by bit, wound by wound, until they’re sobbing and laughing, their insides smeared across the carpet.

The hooky story centers on a young couple, Peter (Christopher Denham) and Lorna (Nicole Vicius), who are clandestinely trying to make a documentary about an apparent cult. The movie opens abruptly, ominously, in the dead of night with the couple being driven — they switch vehicles at one point — to a house where a man instructs them to strip, shower and change into new clothes. (Peter has a tiny spy camera in his eyeglasses.) They do, methodically scrubbing their bodies, and then descend into a sparsely furnished basement. There 10 or so similarly dressed people are waiting for what they believe may be salvation in the ethereal form of a willowy young woman, Maggie (Brit Marling), who, in true star style, knows how to make an entrance: veiled and tethered to an oxygen tank.

When Maggie sits down, the party begins in earnest. Without her veil and nasal prongs, dressed in light, loose garments, her long blond hair cascading down her back, she looks like any number of California girls, one of those pretty young women from Kansas or Iowa looking to break into the movies. Maggie is on a different journey, and while the detours and destination of her path are vague, she makes for a mesmerizing traveling companion — or, more rightly, guide. Because Maggie is the reason that Peter, Lorna and the rest are here, and she knows it, feeds on it. Talking in a soft voice she gives them exactly what they need: attention, hope, a break from the past, a bead on the future. Even as Peter and Lorna keep trying to make their film, they’re not immune to her.

Is Maggie a Manson, a Madonna or perhaps something else entirely? That’s the question that the director Zal Batmanglij and Marling, who together wrote the script, keep teasingly open. Peter and Lorna are adamant that they already know the truth, at least before Maggie starts boring into their heads (much as the filmmakers try to do with us). Peter is particularly zealous, confusing belief with knowledge. Whether he can actually see what’s happening, inside the basement and out, plays into the movie’s ideas about the push-pull between reality and the world of appearances. In a nice touch, Peter makes a living as a schoolteacher, which suggests he isn’t exactly an innocent when it comes to indoctrination.

From the start, when the word "one" slams on the screen, beginning a count that divides the story into 10 sections, Batmanglij gives the movie an appreciable air of unease. Like Peter and Lorna, you don’t know whether Maggie’s the real deal — though the better question is what type of deal she is offering. Is she a friend, foe, fool or just another La-La Land guru peddling transcendence? Marling, raising her voice only occasionally and keeping her gestures largely relaxed, makes restraint work for her, which fits the movie’s increasingly claustrophobic vibe. Maggie erupts only periodically, and when she does it’s always other people’s fault: They are withholding, cowardly. One moment she’s a caring therapist, the next an acting coach and then the personification of a superego.

Batmanglij and Marling do better when they’re working through the material, especially in the basement sessions, then tying everything together, and their big finish, while pleasingly surprising, is the kind of tricky deus ex machina that needs better finessing. The movie’s ambitions are modest, but within its narrow parameters — with sets that look as if they cost about two bucks and grayish digital visuals that make you yearn for film — they create a plausible, recognizable world about characters engaged in that most fundamental search: for the meaning of life. Marling, who also starred in and was a writer on the recent independent feature, Another Earth, another low budget movie that intelligently made the most of its limited means, appears to be on her way to figuring out that question.