We know the minute we see the old man strike up a conversation with the young woman that she’s a ghost. Serene, silent and spectral, it doesn’t matter that he chats as if they’re old acquaintances. Something about him (Yannawoutthi Chanthalungsy) and her (Noutnapha Soydara) suggests that they’ve met this way, on this long dirt road in rural Laos, many times.

The latest feature from Mattie Do, the LA daughter of Laotian refugees who moved back to Laos to become the country’s “only female filmmaker,” is a quiet and ominous story set in the future, but scripted and acted like an ancient folk tale. “The Long Walk” isn’t exactly a thriller, more of a mystery. And it’s science fiction with the barest traces of that genre in its slow-moving narrative.

But whatever you call this unicorn filmed by a unicorn, it’s engrossing and arresting.

We wonder about the old man from the start. He gathers scrap to sell in his village market, gets paid via an electronic implant in his arm, and seems to always be walking, with or without that lonely young woman who knows him but never speaks.

We’ve seen skulls half-buried in the dirt, and women suffering grievous injuries. There’s someone missing from that market. And as he always seems to be around these activities, we size him up as a serial killer or a shaman, because when the cops interrogate him and poke around his house, it’s as if they suspect him and also want him to contact the missing and presumedly dead woman.

A boy (Por Silatsa) lives along that same road, the son of an ill-tempered , hard-drinking father and sickly mother. The kid sees the young woman, too. And when the old man and the boy meet, what the child is told about her and himself is troubling, mind-blowing and illuminating for this tale of the unsettled dead and the superstitious, confused living.

They’re not the only ones. The Christopher Larsen (“Creepshow”) and Douangmany Soliphanh script is cryptic, giving up in secrets in tiny, belated servings. Director Do (Larsen wrote “Dearest Sister” for her, and they co-wrote “Creepshow”) patiently doles out clues and fixates on tone and the novelty of the setting.

It may be the future, but Laotian burial practices and rituals are treated as eternal. Characters like the old man leave oranges at roadside shrines, which the ghost eats and shares with the boy. There’s modernity, and a shamanistic “commune with the dead” tradition in addition to the mystery of who these women were or are and who is making them vanish, leaving their families grasping for closure.

Deaths we witness aren’t happening in real time, but in the past, the future or some Mobius loop containing both.

The patient storytelling won’t be to every taste, and truth be told, not a whole lot happens over the course of these 111 minutes. This isn’t jolting horror, and nothing about it could be pitched as “scary.”

But Do isn’t just an “only Laotian” novelty act. She’s not making commercial films (this 2019 festival film is just now earning distribution), and while there’s always a place at film festivals for movies from an exotic, little-filmed locale set in an exotic culture, one has to hope she’ll figure out “action” and how incidents, not tone alone, make for entertaining drama that plays beyond the film festival circuit.

Still, there’s style and a vivid sense of place in this most unusual movie, a film of future tech and sonic booming jets and unelectrified farms where the work is still done by hand, the way it has been for hundreds of years.

That makes this “Walk” long, but rewarding in the end.

Rating: unrated, violence, profanity

Cast:Yannawoutthi Chanthalungsy, Noutnapha Soydara, Por Silatsa, Vilouna Phetmany

Credits: Directed by Mattie Do, scripted by Christopher Larsen and Douangmany Soliphanh. A Yellow Veil release.

Running time: 1:51