After wandering a lawless land of cannibals, the heroine, Arlen (Suki Waterhouse, top), reaches a promised land. (NEON)

As she demonstrated with her debut feature, the black-and-white, Farsi-language feminist vampire fable “A Girl Walks Home Alone at Night,” filmmaker Ana Lily Amirpour is very good at weirdo world-building. Set in a dystopian near-future, her follow­-up to that 2014 film is called “The Bad Batch,” and the universe that this new movie conjures — a wasteland where examples of America’s human garbage struggle to survive in an unforgiving desert dotted with trash heaps and encampments of cannibals — feels dizzyingly extreme and disturbingly plausible.

“This isn’t real,” reads a sign in one of the last outposts of human decency, a sanctuary city called, appropriately enough, Comfort, and run by a benevolent despot called the Dream (Keanu Reeves). At the same time, it feels sickeningly persuasive, given some of the violent, divisive rhetoric currently polluting civic discourse.

It is into the community of Comfort that Arlen (Suki Waterhouse) has wandered, after being cast from civilized society, for reasons unknown. Although the no man’s land into which she has been thrown is populated by the undocumented, the sick, the insane, the poor, the weak and the criminal, the film’s heroine seems pretty well adjusted. The same can’t said for the savages who waylay her on her way to Comfort. Known as the “bridge people,” the group of man-eaters quickly capture Arlen and harvest one each of her arms and legs for food.

The Dream (Keanu Reeves) addresses a gathering in Ana Lily Amirpour's “The Bad Batch.” (NEON)

After Arlen escapes to Comfort with the daughter of a woman she has killed in self-defense — a little girl named Honey (Jayda Fink) — the story fast-forwards five months to a time when Arlen is able to hobble around on a prosthetic leg while listening to the Dream expound on his philosophy of governance: “I make s--- go away,” he tells Arlen, because of the infrastructure that he has established in Comfort, a frontier town surrounding the palatial residence in which he lives (with a harem of gun-toting pregnant women, all wearing T-shirts that advertise “The Dream is inside me”).

The allegory is, at times, unsubtle, yet there are also moments of surreal, poetic beauty. One nighttime shot captures the aftermath of a Comfort block party, the centerpiece of which is an RV tricked out to resemble a giant boombox, from the inside of which the Dream’s court DJ plays dance music to lull the masses into a false sense of complacency.

It’s a futuristic equivalent of Nero fiddling while Rome burns.

The problem with “The Bad Batch” is that, despite such lovely, otherworldly touches, there isn’t much narrative conflict, once Arlen escapes from the bridge people’s abattoir to Comfort, a place where street vendors sell noodles, not human flesh, but in which the leader exerts a cultlike supremacy over his subjects. The plot, such as it is, is largely fueled by Honey’s father (Jason Momoa), a cannibalistic loner known as Miami Man who wants his daughter back. How and why Arlen agrees to help him achieve that goal is the main question of the film.

At least, ostensibly.

In addition to presenting a parable about the collapse of society, Amirpour’s film is also a kind of postmodern Adam-and-Eve story. Comfort may be Edenic — at least compared with the open desert — but it isn’t necessarily a place where you would want to raise a kid. After all, it isn’t real, as the sign says. “The Bad Batch” suggests that it might be better — or at least less delusional — to fend for yourself among people who make no secret about wanting to eat you.

R. At the Angelika Pop-Up at Union Market. Contains violent, grisly images, obscenity, drug use and nudity. 118 minutes.