They’re all alone out there, tending their desert farm, feeding their pigs, making their own entertainment.

Dad (Jonny Lee Miller) distracts little Remy (Brooklyn Prince) with joke-threat contests, stories and star-gazing. Mom (Sofia Boutella) handles the home-schooling, and sometimes sings and plays the guitar.

But there’s something they’re not telling their tween, something beyond “Earth isn’t what it once was.” There’s a reason Remy and her dad have a running gag about her running away.

“You gonna stay?” He always wants to know. And smiles or not, he’s never sure of the answer. She’s restless and lonely. And she’s a smart, curious kid.

In “Settlers” their dry, desert frontier is on Mars, a modular habitat farm that is weathered and breaking down. They can’t be all alone, but when their daughter remarks about “strangers nearby,” they assure her that can’t be true.

Her waking up to the sounds of pig squeals and a bloody “LEAVE” painted on their window reveals the Big Lie. They aren’t alone, and the two adults’ quick reaction — he grabs a rifle, she’s palms a knife — show they recognize a familiar threat.

Whatever they have on this barren but oxygenated piece of Mars, they’re prepared to defend. Whatever they have they might not have come by via the usual means. And whatever it takes, when interlopers come for their kid, blood will be spilled.

“Settlers” is what happens after that fight, when Dad dies and somebody else (Ismael Cruz Cordova) comes in, armed and expecting to take his place.

Writer-director Wyatt Rockefeller’s debut feature is kind of the anti-“Martian,” a downbeat and almost forlorn “Twilight Zone” parable of sci-fi tropes running up against basic human nature.

It has a “Silent Running” vibe, with a hint of “Planet of the Apes.” Remy will discover things that have been kept from her, things that the viewer might figure out before her. She might long to learn more, rebel against her circumstances. But how much knowledge is too much? And no matter how far you travel, your humanity and the base corners of human nature travel with you.

Boutella (“The Mummy”) is properly protective and panicked, when the character’s need arises. Prince (“The Florida Project”) is as impressively moody and mercurial as Remy (Nell Tiger Free plays her as an older teen). Miller’s father figure walks a line between amused and manic.

And Cordova (TV’s “Berlin Station”) brings a wary weariness to Jerry, a man who has all the information, has his doubts and yet somehow clings to hope.

The terrain (South African desert is this version of “Mars”) may be as sci-fi familiar as the story Rockefeller tells upon it. The violence, when it comes, can be jarring and depressing, even off camera.

But with “Settlers,” the filmmaker takes us on a journey as much internal as extra-terrestrial. It’s an intimate, sober and downbeat sci-fi Western, one with an inevitability that reminds us of what Buckeroo Banzi was warning us about all those years and dimensions ago.

“No matter where you go, there you are.”

MPA Rating: unrated, bloody violence

Cast: Sofia Boutella, Brooklyn Prince, Ismael Cruz Cordova and Jonny Lee Miller

Credits: Scripted and directed by Wyatt Rockefeller. An IFC Midnight release.

Running time: 1:43