“Aquaman” and “Dune” hunk Jason Momoa figures prominently in the advertising for “The Last Manhunt.” He’s in just three or four scenes in it, but he co-wrote the story, so fair enough.

And he’s the one who got this new version of the story of “Desert Runner” Willie “Boy” Brown on film. This “true story” Western is a tad malnourished, stolid and depressingly downbeat. But it’s a tragic story. Even if you use a lot of Native American actors and Native American plainsong in the score, it would take a special touch to spruce up the few moments of action, lift the pathos of the couple on the run and make the quarrelsome posse entertaining enough to watch.

That touch is mostly missing here. But the story is still fascinating.

Willie Boy Brown was a Chemehuevi Indian (Southern Paiute) who tried to run off with his distant cousin girlfriend after accidentally killing her disapproving father. He’s been the subject of legend, lore, a book titled “The Last Manhunt” and a 1969 Western — “Tell Them Willie Boy Was Here” — starring Robert Redford as the reluctant sheriff hunting the fugitives, and Italian American actor Robert Blake in the title role.

Set in 1909, “Manhunt” is a “closing of the West” tale, a literal last posse-on-horseback “manhunt” through Joshua Tree, Twentynine Palms and environs, promising striking scenery, tragic young love, endless searching for water as well as the man the posse is hunting, and violence.

Martin Sensmeier of “Wind River” and “Yellowstone” is Willie, Hawaiian actress Mainei Kinimaka (of the Momoa TV series “See”) is Carlotta, the daughter of a medicine man (Zahn McClarnon) who has to track down the 16 year-old to save her from an “inappropriate” match. “You’re BLOOD,” he reminds them both.

That won’t stop Willie Boy. His second meeting with the father over his beloved leads to an argument and a shooting. Tribe members, who tracked them down when they tried to run off the first time, are ready to do it again. But a shooting means the recently-widowed, depressed and crawling into a bottle sheriff (director Christian Camargo) is involved now, with an armed posse of men of varying abilities and tolerance.

A reporter (Mojean Aria) cynically tries to join their crew, willing to manipulate the story which he recognizes needs some sizzle — an editor lowers Carlotta’s age to 14 — and that “You lack a great ending.”

The opening acts have the novelty of filming an under-filmed part of the desert southwest, with palm trees and Joshua Trees and deep canyons adjoining the vast expanse of desert. But the leads are just bland and there’s no sugar-coating that.

The middle acts, posse-centered, are talky and argumentative and don’t have quite enough conflict to engage the viewer.

And the finale can’t get here soon enough.

Momoa, playing a Native named Big Jim, turns up here and there, not enough to add spark to a picture whose score sets the tone, and is eventually overwhelmed by funereal strings — lots of cellos in tears.

I appreciate the effort it took to get a Western made in this day and age. It’s a good story. Redford knew it. So does Momoa. And there are some scattered stand-out moments.

But the relative poverty of the production shows in every too-clean-to-have-been-hiking-through-the-desert costume, every wish-they-could-have-cast-a-pricier, showier actor or actress, every “Let’s hire a script doctor to tighten/quicken/juice-this-up” suggestion ignored.

Rating: R for some violence and language

Cast: Martin Sensmeier, Mainei Kinimaka, Raoul Max Trujillo, Brandon Oakes, Amy Seimetz, Mojean Aria, Christian Camargo and Jason Momoa.

Credits: Directed by Christian Carmago, scripted by Thomas Pa’a Sibbett, Jason Momoa. A Saban Films release.

Running time: 1:43