Martin McCann in "The Survivalist"

One of the few things that can be said about “The Survivalist” without spoiling its many twists is that you never know the full extent of the world beyond the one that exists beyond the acre that the nameless titular character (Martin McCann) has created for himself in the forest. There are hints of the civilization he left behind, a lot of which was presumably wiped about by starvation to judge by the ferocity he protects the small garden that sits in front of his heavily boarded up house. And it’s dire enough for one of the few who dares approaches, a woman named Kathryn (Olwen Fouere), to offer up the sexual services of her teen daughter Milja (Mia Goth) if only the two could come inside. But first-time feature director Stephen Fingleton does well never to tip his hand, perhaps because the one he’s created inside the cramped cabin between the trio of characters, none of whom particularly trust each other, is so intriguing all on its own.

“The Survivalist” opens with a timeline of the world population that blurs its chronology as it goes haywire, conveyed so simply that it’s terrifying to consider such a thing could be reduced to a graph. Fingleton only amplifies the dread from there, even though he operates at a slow burn with plenty of fire to ignite. The man he finds in nature has been there for seven years, once with a brother, with his routine of setting bear traps and securing the many locks on his door suddenly upset by the arrival of Kathryn and Milja, who are only slightly less weary of him than he is of them. There is no score to break the tension, giving even more importance to each word spoken, already carrying considerable weight with the man’s hair trigger meaning just one misconstrued turn of phrase could be the difference between life and death for the women.

But the man gradually begins to lose control, not necessarily of the situation, but of the film as Milja becomes “The Survivalist”’s most pivotal character. As played by the blank-faced Goth, who memorably first graced screens in Lars von Trier’s “Nymphomaniac,” Milja’s loyalties are never entirely clear until she acts, seemingly forming a bond with the man with whom she’s now carnally involved but nodding in agreement when her mother whispers plans to kill him when he’s out of earshot.

Singleton, who never repeats the same angle twice visually, is equally dynamic with his screenplay, continually coming up with new angles for the relationship. When one small piece changes, it sends ripples through the whole and though a sense of humor is nowhere to be found in these woods, one can’t help but smirk as “The Survivalist” grows darker and darker with one twist nastier than the next. Yet as the film largely depends on emotional violence for its drama, it doesn’t spare on the physical action, never letting the audience forget the peril that awaits around every corner in this post-apocalyptic wasteland.

The moments are few and far between where Fingleton shows his first-time status, having honed his talent at establishing a distinctive tone and flair for naturalism on a series of shorts before “The Survivalist,” though one particular metaphorical flourish towards the end suggests some youthful overreach. But the considerable ambition of “The Survivalist” is often met, anchored in strong performances from all three of the central actors and a filmmaker in great command of his skills, like his characters going back to basics to build a strong foundation for something that will endure.

“The Survivalist” was recently picked up for U.S. distribution by Alchemy.