Director: Shane Carruth
Stars: Amy Seimetz, Shane Carruth, Andrew Sensenig, Thiago Martins, Kathy Carruth, Meredith Burke

In 2004, hardcore and, more importantly, adventurous science fiction fans were blown away by a little independent time-travel film called Primer. Written and directed by first-time writer-director Shane Carruth, it's an astounding piece of brainy, uneasy plotting that, nine years later, still holds up for many as the best time-travel film ever made—a bold statement, sure, but singular experiences like Primer provoke such hyperbole.

Stemming from that response, the film's passionate supporters have since been anxiously awaiting Carruth's next move, and when his sophomore feature, Upstream Color, premiered at the Sundance Film Festival two months ago, the reactions ranged from emphatically positive to pass-the-Tylenol disorientation. At the very least, Carruth didn't disappoint.

Now that Upstream Color has elicited the same impact here at SXSW, there should be little doubt: The man remains indie cinema's most exciting new voice. And Upstream Color—an ambiguous and puzzling head trip that'll no doubt reward those who give it multiple viewings—is a surge of free-flowing imagination that tops Primer.

It's also a textbook example of a movie that's best seen with little to no prior knowledge of its plot machinations. But here's a little something to whet curious film buffs' appetites: Two morose strangers (Amy Seimetz and Carruth) meet on a train, slowly begin seeing each other, and have no idea that they share a common past experience that neither one of them truly understands. Somewhere not all that far from their city, meanwhile, resides an eccentric farmer with a giant pen full of pigs. How all of those pieces connect is what Carruth challenges audience members to formulate for themselves—the necessary details for comprehension are there, but laid out in such a way that posits Upstream Color as a slightly less menacing relative of Mulholland Drive.

Carruth is working on several artistic levels here. The film's core is the whirlwind romance, but, true to his idiosyncratic form, Carruth surrounds that beating heart with other particular influences, including body horror, bleak drama, and (bizarre) biology. Which, on the whole, could leave viewers cold if not for his ability to capture moments of sublime beauty.

Even at its most impenetrable, Upstream Color is a superb technical achievement. For its nuts-and-bolts filmmaking alone, the film is one to seek out immediately upon its April 5 self-distributed theatrical release. Just be sure to bring thinking caps and an open, willingly susceptible mind.