“The Wall of Mexico” is an arch allegory about immigration, about the “haves” building walls to limit access by the “have-nots.”

It’s clever enough, with its story of a prosperous, long-established Mexican-American family blocking local access to its treasured well crystal clear in its messaging to most anybody watching it. But then the filmmakers outsmart themselves with a clumsy, “the moral of our story” over-explained finale.

It’s OK. We get it. And “saying the same thing twice is not inherently a waste of breath,” the film’s one repeated quip, doesn’t let you off the hook for this blunder.

Jackson Rathbone of “The Twilight Saga” and TV’s “The Last Ship” is Donovan, a Floridian newly-transplanted to the American Southwest, and a new night-watchman/gardener/handyman for the Arista family, whose sprawling hacienda screams “old money” to the other folks in Winfield.

Patriarch Henry (Esai Morales) keeps a close eye on the family business, but not on his two daughters. Tania (Marisol Sacramento) and Ximena (Carmela Zumbado) are beautiful, educated, cultured and louche. They’re also childish hard-partiers who carry the confidence of their class in every mean-girl dismissal.

“Godless, arrogant, sick-minded brats who are a waste of water,” is how the older hired hand (Xander Berkely) sums them up.

“They’re nice to me” the new kid protests.

“For a minute.“

Don tries to pass for a local, or at least an Oklahoman, with his sh–kicker boots, hat and drawl. But the townsfolk wonder about him working for “the Mexicans.”

“Don’t drink the water,” they joke. Don figures that’s just some racist thing he doesn’t get, until Henry insists that he shed some of his other duties and “camp out by the well.” Locals are draining it. And that water? It’s special.

Don doesn’t mind, just so long as the mean girls keep inviting him to sample their lifestyle, their cocaine and their other appetites.

“So, what are we celebrating?”

“You shouldn’t think of champagne that way. That’s unfair to champagne!”

It can’t last. And that well? It’s going dry. Slow-on-the-uptake-Don wonders what the heck is going on here.

Co-directors Zachary Cotler (he also wrote the script) and Magdalena Zyzak ladle on the indolence and hedonism in scenes with “the girls,” who switch to Spanish whenever they want to mock Don’s naivete with their cokehead pal Corkscrew Juan (Moises Arias).

They’re all as witty as they are cruel, with Corkscrew an endless supply of jokes in Spanish insulting “gringo rednecks” and “Mexicans.”

“What’s the difference between Jesus Christ and a Mexican? Jesus doesn’t have a tattoo of a Mexican on his chest.”

It’s not about race, kids. It’s about class. Always.

The mystery about “the well” isn’t that mysterious, but what it symbolizes only becomes clear when Henry resolves to stop the “trespassers” from sneaking onto his property to steal from it. That’s what gives the film it’s title, “The Wall of Mexico.”

The attractive young people do what attractive young people do, right up to the point where class is threatened. The well that divides the community (Mariel Hemingway plays the mayor) becomes an interpersonal chasm, not just a social one.

And in case anybody misses what this is all about, the smarter sister makes a point of imperiously explaining it at the story’s coda, straining to prove that “saying the same thing twice is not inherently a waste of breath” but in cinema storytelling terms, failing.

MPAA Rating: unrated, drug abuse, sex, nudity, profanity

Cast: Jackson Rathbone, Marisol Sacremento, Carmela Zumbado, Moises Arias, Alex Meneses, Xander Berkeley, Mariel Hemingway and Esai Morales.

Credits: Directed by Zachary Cotler, Magdalena Zyzak, script by Zachary Colter. A Dark Star release.

Running time: 1:44