The greatest science-fiction films, like the greatest horror films, usually channel the sublimated terrors of their era. Metropolis expressed fears about the class divide back in the 1920s. Invasion Of The Body Snatchers turned the 1950s' communism-related paranoia into an eerie metaphor. Anxieties over the space race became a dominant theme in science fiction from Sputnik to Alien. And the urge to angst over whether any given new form of technology will wither our humanity is as old as the genre, and as new as Ex Machina's fresh take on the theme.

Which is part of the reason an alien-invasion drama like The 5th Wave feels so fundamentally hollow. The film, which adapts Rick Yancey's bestselling 2013 young-adult novel, doesn't tap into any particular collective concern, or into any ideas larger than a one-foot-in-front-of-the-other action-adventure. At best, it tries to tap into the way the Hunger Games books and films turned embattled teen-girl heroes into a profitable cinematic movement, and Twilight turned teen love triangles featuring dangerous, exotic boys into a craze. It feels more commercially conscious than culturally conscious: it's out to build a franchise and an ensemble of tough, lovable characters capable of selling another two films. But that means it's working from a familiar framework about teen empowerment in crisis. And the film version doesn't have many distinctive elements to flesh out that framework, or to make this look different from any of the other dystopian post-apocalypse novels that have flooded teen-lit shelves over the past decade.

"When you're in high school, just about everything seems like the end of the world," 16-year-old Cassie Sullivan muses in an early-film flashback to her pre-apocalypse life. Briefly, the film does find some resonance in the way calamity instantly puts a nostalgic gloss on every mundane memory about parties, crushes, and family hangout time. That ordinary world is eradicated when aliens arrive, bringing a series of catastrophes that wipe out much of humanity. In the first wave, all vehicles and power stop working. In the second, earthquakes and floods devastate the world. In the third, an engineered super-disease tears through the survivors. In the fourth, the aliens themselves arrive, taking over select humans as a form of perfect disguise.

The idea of aliens stealing human bodies is a classic science-fiction trope, and with good reason: it cuts to the core of our lizard-brain fears that it's impossible to know what other people are really thinking, or what they might be concealing. And if the protagonists are threatened with takeover as well, as they are in films from Body Snatchers to The Host, it connects to the equally common, equally naked terror of losing physical or mental control.

But The 5th Wave's biggest disappointment is the way it handles body-theft as a mundane, almost casual threat. It makes trust harder, since anyone could be an alien, but it's overtly more a plot device than a dread the characters internalize or examine. The script (by industry vet Akiva Goldsman, his Fringe co-conspirator Jeff Pinkner, and Erin Brockovich writer Susannah Grant) falls back on weak, plaintive language: "They look so human," not "They're stealing human bodies, and might steal mine next." There's no sense of how the aliens claim bodies — any information about them is sketchy and contradictory, for reasons revealed later in the film — and no sense of what it might mean for their hosts. It's a horrifying scenario that's played without the horror, almost offhandedly.

The film's other emotions are equally flat. Cassie (Chloë Grace Moretz) makes sad faces when her parents die and scared faces when she's being chased or shot at, but most of her personality — and agency — disappears once she starts falling for Evan Walker, a handsome stranger who saves her life. (Alex Roe, who plays Evan, is visibly seven years older than the 18-year-old Moretz. He's a high school girl's fantasy of a college grad boyfriend, which might sound dreamy in teen-focused erotica, but makes him look disconcertingly predatory on the screen.) Their romance is one of the many elements in the film that feels like it's working from a checklist: distrust (he could be an alien!), cautious alliance (he's super useful, though!), burgeoning pants-feelings (he's so hot in that tasteful waist-up shot of him bathing in that lake!), and so forth.

But neither Moretz nor Roe connects with the emotions behind the checklist. When Roe earnestly reveals a life-changing secret from his past, he does it with the bland, sleazy earnestness of a dude telling his current fling that he hasn't actually gotten around to breaking up with his last girlfriend yet, but he was just about to text her, really. Meanwhile, Cassie's little brother Sam (Zackary Arthur, from Transparent) and her crush-object Ben (Nick Robinson, recently of Jurassic World) have more reasons to give grim, buttoned-down performances as they're subsumed into an Air Force base where the military is training children as soldiers. But the scenes on the base are awkwardly, inconsistently handled. Liev Schreiber distinguishes himself as the base commander, alternating warmth with menace, and doling out stirring inspirational speeches on cue. But Maria Bello, playing a key recruit-processing sergeant in the world's least flattering hair-do, plays her role almost comically. And the military-movie posturing between the kid recruits comes across as just short of laughable, as though the film is shooting for Ender's Game coldness, and instead winds up with a G-rated, junior-grade version of Starship Troopers camp.

Made for a relatively cheap $38 million, The 5th Wave frontloads its budget and its spectacle into a few powerful, chilling early shots of disaster-movie-style world devastation. But after that, it feels like it was made on the cheap, as if the body-snatcher idea was just an excuse to avoid designing actual aliens. Pitch Perfect director J Blakeson gets some striking shots out of his kiddie Full Metal Jacket sequences, as the child recruits try to bury their fear under discipline and obedience. But other sequences are distractingly, impenetrably dark. The action is frequently too chaotic to register, and the performances are monotonal. There's no personality in this story, or the way it's told.

Yancey's novel The 5th Wave is the first in a series, and it ends with few questions resolved, from the aliens' real nature to Cassie's conflicted feelings for Evan to the question of why Maika Monroe's gothy tough-girl character Ringer gets such a hero's build-up, then does so little with it. (Spoiler: She's central to the second book, which came out in 2014. The third is due out later this year.) The obvious sequel setup recalls The Hunger Games films, or Maze Runner's "That was quite an adventure, I wonder what's next?" epilogue. But nothing about 5th Wave makes a second installment feel tempting. It's common enough for science fiction to explore inner space instead of outer space. But this franchise never comes across as interested in either. It depicts a dim future for humanity, and a dimmer present for its genre.