Grade: A-

So, it's a pretty classic set-up: would-be filmmakers Peter (Christopher Denham) and his girlfriend Lorna (Nicole Vicius) infiltrate a mysterious cult in an effort to expose its ringleader as a fraud, but soon find themselves in way over their heads. The mesmerizing Maggie (Brit Marling) claims to be from the future — the year 2054 to be exact — and she's a far cry from crazy-eye Charles Manson... Think more along the lines of an innocent-looking, barefoot, blonde-haired hippie who wanders around an underground bunker in flowing white robes and furry Free People sweaters with oxygen tank in tow, leading peaceful singalongs of The Cranberries, mass worm eatings, and mass... vomitings?

Yes, there are a few of those, so if you're squeamish... be prepared for a few nods to Fear Factor. But for the most part, this is a very low-budget, low-key, dialogue-driven drama that is ultimately more atmospheric and ambiguous than horrific. The sets and costumes and characters and interactions are perfectly normal, even verging on banal — this film is decidedly devoid of special effects — but this initial normalcy makes it that much more intense when you get into the thick of things. I'm thinking in particular of a scene in which Maggie confronts Peter's alienation from the group (or more specifically, the groupthink that compels even Lorna to vomit on command) and taunts him mercilessly with memories of childhood abuse.

And later, we find out that even this scene may not be all that it seems. Or is it? “Sound of My Voice” maintains this flighty, teasing dance between maybes and what-ifs until the very end. Peter, the die-hard realist who swallows radio transmitters and wears a tiny camera on his glasses, ultimately must confront a side of himself that is far less understandable: blind faith in the unknown.

It's not your typical mystery, and it's not quite sci-fi. It's certainly not a film for those who are uncomfortable with large grey areas and a glaring lack of clear-cut answers. And as often happens when a screenplay takes itself very seriously, there are some moments that ultimately translate more tongue-in-cheek than (maybe) they should. I had to stifle a few chuckles, for example, at the awkward group dance scene and over-the-top secret handshake — a sort of bizarre combination of spirit fingers and Miss Mary Mack, with a couple Kappa Sig snaps thrown in for good measure.

But atmospherically-speaking, this film is close to perfect... and may have you questioning the cosmic intentions of every willowy blonde who walks by.