Should the apocalypse strike and any of us happen to survive it, you can’t accuse the movies of leaving us unprepared. Dystopian futures are a dime a dozen in science-fiction cinema these days, with a generally shared aesthetic that leads us to expect, for better or (probably) worse, a lot of damp, ashy slurry and unflattering sackcloth. In some ways “Vesper,” with its drenched khaki palette and all-encompassing air of ruin, conforms to this forecast. In others, Kristina Buozyte and Bruno Samper’s solemn, elegant fantasy surprises with its textured, sometimes iridescent world-building: There’s beauty to be found in this vision of Earth in a state of ecosystemic collapse, even if it’s hard-won and harder still to nurture.

Premiering in the main competition strand of this year’s Karlovy Vary festival, “Vesper” marks a long-awaited return to feature filmmaking for Lithuanian director Buozyte and her French writing partner Samper, now assuming a co-directing credit. Their 2012 collaboration “Vanishing Waves,” a vividly original blend of cerebral sci-fi and sensual eroticism, found a keen following on the genre festival circuit as well as widespread international distribution. (Between now and then, the pair have completed only a segment of the Drafthouse horror anthology “ABCs of Death 2.”)

Delivering on the atmospheric formal promise of their previous film while simplifying the storytelling — and switching to English, though the Europudding DNA of this Lithuanian-French-Belgian co-production feels fitting for a post-nations vision of the future — “Vesper” is a more accessible, youth-targeted effort, already picked up by IFC Films for release in North America. This is effectively arthouse young-adult fare, crediting adolescents with curious minds and strong stomachs.

Steely 13-year-old Vesper (impressive up-and-comer Raffiella Chapman) certainly has both those things: As a child largely fending for herself in a distant future where the planet can no longer generate new plant or animal life, her wits and nerve are pretty much all that keep her from death. Her father Darius (Richard Brake) is frail and bed-ridden, though he manages to accompany Vesper on her exploits via a drone that acts as a mechanical vessel for his mind and voice; her mother succumbed some time ago to a virus that transforms its victims into faceless, drifting “pilgrims.”

Meanwhile, Darius’ brother Jonas (Eddie Marsan, in slitheringly villainous mode) is not an uncle to be counted on. Lording over a neighboring farm where he enslaves child laborers to harvest what little the ground has left to yield, he has his sights set on his niece’s strength and smarts. Little does he realize her full potential, however: In a secret, shabby greenhouse, Vesper conducts ongoing experiments in synthetic biology, rearing strange, luminescent new life forms — exquisitely rendered by the film’s visual effects team — against the scorched-earth odds.

This cruel social hierarchy exists entirely outside the true realms of privilege in a dying world: elite, elevated citadels, where wealthy oligarchs live comfortably on the fruits of advanced biotechnology, served by a manufactured class of humanoid AI beings called Jugs. Vesper has knowledge that would be of value in these isolated communities, but no line of access to them. So when, in the scrubby wilderness, she encounters Camellia (Rosy McEwen), the refined daughter of a fleeing citadel resident, she sees a chance to change her fortunes.

Though the film’s original screenplay, co-written by the directors with Brian Clark, seemingly pulls from a number of obvious genre forebears — from scene to scene, one might identify stray accents of “Children of Men,” “The Road,” “The Hunger Games” and even video-game smash “The Last of Us” — the result is never quite generic, with an unsentimental but darkly romantic spirit of risk and peril that feels informed as much by pre-Disney literary fairytales as any science fiction. Chapman’s stoic but winningly vulnerable performance likewise keeps proceedings humane and honestly felt: Where so many YA heroines amount to dauntless adults in children’s bodies, she plays the title character as a changeable, characterful child thrust into unreasonable adult responsibilities.

Still, it’s the sophisticated technical realization of this desperate dystopia that startles most here, achieved on a budget presumably a fraction of that granted to most franchised Hollywood fantasies, yet with burrowing imaginative detail and a tactility that eludes so many of the multiplex’s soupy CGI extravaganzas. Vesper’s living laboratory of intricately shaped hybrid plants — shimmying and shimmering like jellyfish, in soft fluorescent shades that sing against the autumnal rot of the surrounding landscape — are the dazzling digital coup of a film otherwise reliant on practical effects, the dusky shadow-play of Feliksas Abrukauskas’ lensing and the tangible wonders of Ramūnas Rastauskas and Raimondas Dičius’s production design. Their economical sets foreground the handmade ingenuity of humans living off a barren land, hinting at the more technologically advanced world of the citadels via the ghostly, tentacled structures that loom menacingly on the horizon. “Vesper” is a sci-fi film fascinated by earthly survival, not sleek, state-of-the-art spectacle — though it often dazzles just the same.