Shane Carruth is more than happy to talk about his remarkable new film “Upstream Color” in substantial detail, poring over its staggered themes and elliptical construction with a discursive chattiness that suggests he, too, is still discovering further possibilities within it. Just don't ask him for a nutshell synopsis.

“Here's the thing,” he says breezily, after I ask him if such summarization is even possible with this glistening glass onion of a film, a kind of physiological romantic thriller suffused with surgical sci-fi. “Because that's something I've been so averse to, I've tried to craft the marketing in such a way that conveys what's on the film's mind. I'm more comfortable with creating trailers and key art that suggest what the film is, that encapsulate and maybe even contextualize it, more than I'd be willing to synopsize it.”

What Carruth refuses to do, many a critic has painstakingly attempted since “Upstream Color” dazzled and flummoxed audiences in equal measure at the Sundance Film Festival in January – the same festival, of course, where Carruth's equally teasing, genre-melting debut feature “Primer” won the Grand Jury Prize in 2004. The internet is awash with reviews and navigational articles boasting an authoritative interpretation of the film; inevitably, hardly any of them overlap completely.

Two viewings later, I feel neither qualified nor inclined to join the critical code-cracking. There are stray strands of “Upstream Color” that I still find inscrutable, which is not to say I'm not moved by them. Carruth, who also acted as his own writer, cinematographer, composer, co-editor, co-producer and leading man, has fashioned a film that is somehow at once fastidiously technical and emotionally overwhelming; aided by the grandeur of its imagery and sonic design, it's possible to intuitively understand “Upstream Color” even as the brain is still disentangling the narrative's dense series of life cycles.

“Many of my favorite films, if someone were to tell me simply what they're about, I probably wouldn't be that interested,” Carruth says. “Plot often has so little to do with what's at the heart of a film. Maybe this is just stubbornness on my part, but if I don't have to describe it that way, and there's a way not to, then I want to figure that out.”

It may be interfering with the intended approach path Carruth has laid for first-time viewers to say that “Upstream Color” is a love story, though not before it's a serene exercise in body horror. The film's young female protagonist, Kris (Amy Seimetz), is violated with a bio-engineered worm that spawns inside of her; when that biological experiment is countered with another involving pigs, she's left with no memory of the ordeal – only the trauma. 

She finds solace in a similarly damaged man (played by Carruth himself) who appears to have been absorbed into the same ruling life cycle – it's here that the film gives itself over almost exclusively to cinematic language as opposed to dialogue. Oh, and there are orchids. Many orchids. Carruth's right: verbal descriptions, both within the film and about the film itself, don't quite do the trick.

“I basically needed to strip our central character, Kris, of her personal narrative, to make her a raw nerve and a blank slate,” says Carruth. “I needed her to adopt a new narrative based on potentially the wrong information that she wakes up to, to be affected at a distance by things she couldn't necessarily speak to. That's a way into exploring all the things that affect our subjective experience: be it religion or physiology or psychology or pharmaceuticals or ethics or politics systems. All these things come to shape us, or we come to shape them. That was the core of it, so I then came up with a structure around it: this life cycle – of worms, pigs, orchids – to support that.” 

In conceiving the film, the abstract ideas unsurprisingly came to Carruth before the human dynamics did, though the elements ultimately shaped each other: “I knew it was going to be a love story when I started writing the script in earnest. I had been accumulating these ideas, but only as a thought experiment, really. And the more I stripped away these layers of a person's identity, the more it felt really heartbreaking to me. It's horrific to find yourself vacant, not certain of anything. Once it registered how much this person would be broken, that lent itself to a romantic premise. And that's when I fell in love with the story, knowing that would be its heart.” 

Carruth enlisted hot new multi-hyphenate David Lowery (who unveiled his own directorial effort, “Ain't Them Bodies Saints” alongside “Upstream Color” in January's Sundance competition) to edit the film with him; a significant collaboration for an artist who is otherwise so self-sufficient. Did Carruth have the film's splintered narrative planes mapped out beforehand, or did much of it come together in the editing room? 

Guy Lodge is a South African-born critic and sometime screenwriter. In addition to his work at In Contention, he is a freelance contributor to Variety, Time Out, Empire and The Guardian. He lives well beyond his means in London.