"Baghead" takes two disparate genres—a relationship comedy in the mumblecore mode and an eerie thriller one stab wound away from being a slasher film—and juggles them together, creating a refreshingly drastic change of pace from what moviegoers have grown accustomed to expect in today's cinematic landscape of formulaic predictability. Shot lucidly with handheld cameras and styled with a cinema verité approach that drops the viewer off in the midst of lives authentically being lived, writer-director brothers Jay and Mark Duplass have the beats, rhythms, and meaningful silence of everyday human interaction down to a science. When they finally introduce the film's darker potential as a horror movie, their subdued aim for scares is effective precisely because enough unhurried time has been spent with their characters to genuinely care about them as real people.

Beyond all of that, "Baghead" is a motion picture about the natural desire to create art and find meaning in one's existence. In the case of struggling actor friends Matt (Ross Partridge), Chad (Steve Zissis), Catherine (Elise Muller) and Michelle (Greta Gerwig), the former three know full-well that they are aging fast and have but a limited window in which to hit it big in their careers. By comparison, Michelle is younger and more impressionable, just starting out in the business and still without an agent. She also, evidently, has not made it clear that her relationship with the chunky, less-assured Chad is one that she sees as strictly platonic. Carnally, Michelle is more interested in Matt—the one with the "Elvis hair," as Chad enviously tells him—despite his romantic history with Catherine.

Following their attendance at a film festival screening of the dreadfully pretentious indie flick "We Are Naked," the four of them are convinced that they could make something better (and create great parts for themselves while they're at it). Traveling up to a remote house in woodsy Big Bear, California, they set out to tackle writing a screenplay over a long weekend. Their first problem is that they have no idea what their film should be about, and their second is that someone with a paper bag over his or her head is lurking outside. Is it one of them playing a trick on the others, or are they in more immediate danger?

"Baghead" is original and unassumingly earnest, a fascinating slice-of-life impeded upon by the addition of a faceless, possibly dangerous figure into the equation. The filmmaking talent that Jay and Mark Duplass possess is their ability to pull so much from their actors without even needing to say a word. Matt, Chad, Michelle and Catherine could be developed more fully—their individual backgrounds are skimmed over—but an inordinate amount is gauged about who they are and what they want through the way they carry themselves, the way they stumble awkwardly over their intentions, and the way that they always seem to be thinking and taking in information even in their moments of quiet.

Matt and Chad, in their early thirties, have yet to win the kind of acting role that will get them noticed, while Catherine, roughly the same age, seems well aware of the sell-by date on actresses in Hollywood. That they and Michelle endeavor to write themselves a film is well and good, but as Matt asks Catherine in one scene, "How many times have we started something and never finished it?" For Chad, his self-consciousness in his profession—he never seems to be good enough, smart enough, or handsome enough—wins out in a painfully funny sequence where he tries to make a move on Michelle, only for her to cheerily rebuff his advances and compare him to her brother. To make the humiliation worse, Michelle, not out of spite but simply out of cluelessness, starts putting little hairclips all over his head.

When Michelle drinks too much on the first night and falls asleep, she experiences a frightening dream about a person with a bag over their head standing outside amidst the underbrush. It's so vivid the next morning, in fact, that her description wins over Matt on what the premise of their script should be. Idea sessions follow, and so does an ominous occurrence where Michelle comes face-to-face in her bedroom with the mysterious stranger from her dream. She naturally assumes it is Matt who has shown up to scare her, but it turns out not to be. Could the culprit be Catherine or Chad playing a trick on her, angry about her attraction to Matt and out to give her a fright? They deny the accusations, but then, how well can someone really trust the word of actors? This subplot, for the most part taking a backseat to the relaxed interplay between friends, slowly rises to the forefront in the third act. It leads to a scene involving the discovery of an obscured car in the woods that is armrest-clenching in its tension, and a final revelation that is fairly predictable, but also credible and fitting.

Beautifully acted by a leading foursome who never seem to be acting at all—their total embodiment of their characters is the ultimate compliment that can be given to them—"Baghead" carries a loose, conversational quality that allows the audience to feel as if they are right there with them, spending some time with good friends. As the sweetly dippy Michelle, Greta Gerwig is an extraordinary find, her slow-mannered speech either at odds with her brain processes or in perfect step. Gerwig's adorable quirkiness is offset by her unaffected beauty, and she is never less than delightful to watch onscreen. Alternately hilarious, subtly sinister, and finally poignant, "Baghead" is not quite like any other film in memory. The concluding moments are just right, suggesting that the quartet may creatively be onto something that could find them the accolades they've been hungering for. As is typical of Hollywood, though, their success is not a definite, and where they go next has yet to be discovered.