“American Honey” is a movie that takes the temperature of youth culture in a way that no movie has in years. It tells a good story, about a girl named Star (Sasha Lane), 18 years old, with Rasta Barbie braids and a skeptical smirk, who joins a wolfpack of kids in their late teens and early twenties who live on the road, traveling from one cookie-cutter motel to the next, making money by hustling magazine subscriptions door-to-door. They don’t sell their bodies, but in a way they do: Most of them are striking-looking in a trashed-runaway vagabond skate-punk way, and they use their pierced-and-tattooed street charisma to evoke pity and awe. They flirt and charm their way into selling a product that no one really wants.

Andrea Arnold, the British filmmaker who became a critics’ darling with movies like “Fish Tank” and “Wuthering Heights,” has directed “American Honey” in a style that might be described as hip-hop Dardenne brothers. The film looks like a revved-up documentary, with swirling handheld camera that gets in the characters’ faces and trails them on their breathless odyssey to nowhere. But the movie also has an incredible groove. In a parking lot, Star catches the eye of Jake (Shia LaBeouf), a bearded glamour-puss who’s like a cocky, rat-tailed James Dean, and moments later, when she follows him into a Wal-Mart, and Jake and the other kids break into dance moves near the checkout counter to the synth-throb of Rihanna and Calvin Harris’ “We Found Love” (it’s blaring over the store’s speaker system), and Jake jumps up on the counter, which is enough to get a cashier to call security, the scene looks like a pop-renegade epiphany to place alongside every movie from “Jailhouse Rock” to “8 Mile.”

You watch this scene thinking that the kids do look pretty cool, and that “We Found Love” sounds even more orgasmic than it did when it ruled the radio five years ago. For a moment, you’re high on the moment. Yet you also can’t help but notice that this dance explosion in the chain store has a frayed recklessness about it. Star is attracted to Jake, but really, what is she being lured into? It looks a lot like the scraggly last stand of teen rebellion.

What’s wrong with the kids today? That’s a question that adults have been asking ever since the teenager was invented as a stand-alone demographic entity, sometime in the early ’40s. The question tends to make the person posing it sound like a crank. For decades, teen rebellion has been the cutting edge of sexual revolution (how to dress, dance, hook up), and who wants to take a stand against that? A long time ago, teenagers were seen as delinquent destroyers of the status quo, but we now tend to assume that they’re simply leading the way.

Yet when you see “American Honey,” you may feel that teenage rebellion, for the first time, has gone about as far as it can go — that it’s reached a point where it’s consuming itself. There’s a certain mythology that has coalesced around the Millennials, and that mythology says: The Millennials are a terrific generation, sympathetic and enlightened, free of so many of the prejudices about race, gender, and sexuality that have hindered those older than they are. They have great taste in pop culture, and guess what? They’re pretty damn nice. Overall, I wouldn’t disagree with that assessment. Yet it tells only half the story of “the kids” today. For there’s a competing energy out there (seen more in those who have less), one that’s brilliantly evoked by “American Honey.” The movie is about a girl trying to escape a world of no hope, but she does it by joining a group of outsiders who can’t connect with anyone outside themselves. The film’s allure is that it’s not just a story, it’s an immersion, a verité rhapsody about the live pulse of kids in the age of corporate nihilism. The movie is a bulletin — seductive, alarmed, fascinated — told from the inside. It’s the least moralistic youth movie imaginable, and that’s exactly why it’s such a potent warning.

The warning should speak to all of us, because it’s not about the perils of too much sex and drugs and heavy-beat rap & roll, though those things are connected to it. The movie is a warning about the destruction of empathy. The characters in “American Honey” have cut themselves loose from their parents (the implication is that they probably had good reason to — i.e., they came from abusive households), and because they make cash with their magazine semi-scam, the result is that they’re “free.” Or, as one of their favorite lyrics puts it: “I make my own money, so I spend it how I like,/I’m just living’ life,/And let my mama tell it, nigga,/I ain’t living right.” They’re free to fight, and smoke dope, and laugh like demons, and jump around naked in front of the campfire, and give each other the hugs they never got. They’re free to be — to do nothing in the world, really, but exist.

In one of the best scenes, Jake and Star knock on the door of a lovely home in Kansas City (one of the film’s tacit observations is that a major swath of America is now a lavish pastoral suburban paradise — not the one percent, but the Middle American five percent). Jake does his magazine spiel, which involves reeling off a dozen lies with the speed of an unflappable executive. (Hustling, it turns out, really is harder than making an honest living.) After a few minutes, the polite Christian lady they’re trying to sell eases them out the door as if they were invaders from a distant planet, but not before berating her own sweet-faced daughter, whose dance moves in the backyard look as liberated from respectability as anything the movie has shown us. The girl appears to be about 15, but we can see she’s already halfway out the door to Spring Break. The spirit channeled by “American Honey” isn’t limited to no-future runaways. It’s the virus of freedom without a dream.

“Dream” turns out to be the movie’s spirit word, echoed in Bruce Springsteen‘s haunting cover of Suicide’s “Dream Baby Dream,” which Bruce turns into a desperate sequel to “Dancing in the Dark” — a plea to his lover that if they have the faith to dream a life, then maybe that life can come true. Star has a dream too, of sorts: She fantasizes that she can be with Jake, that they’ll move to a shack somewhere and have lots of kids. But it’s heartbreaking, because even though there’s an element of grown-up desire to that scenario, the way Star voices it she’s like a little girl talking about what she wants to be when she grows up. And what her fellow travelers keep telling her, with the dissolve-on-contact sensuality of their live-for-the-moment life, is that dreams aren’t for them. I won’t tell you that “American Honey” is anything like a perfect movie; it goes on too long, falling off in the last act. Yet to watch it is to touch something beautiful and broken in the heart of the first generation of Americans since the ’50s who feel like they don’t have the luxury to dream, and as a result have forgotten how.