A Trojan horse motif permeates the last act of Rupert Wyatt’s would-be action movie about an earth that has capitulated to extraterrestrial invaders and a resistance movement fighting the new status quo, and that’s curiously appropriate: a cinematic Trojan horse, “Captive State” promises to be an exciting thriller, but proves stodgy and dull.

After a brief prologue in which a couple fleeing the invaders through the streets of Chicago, their two sons in the backseat of the car, are stopped by alien enforcers, the picture jumps ahead nine years, when the new regime—with the invaders in charge as subterranean “legislators” and human quislings like Mayor Lee (Marc Grapey), Police Commissioner Igoe (Kevin Dunn) and his second-in-command William Mulligan (John Goodman) acting at ground level to keep order—is in firm control.

But as in old TV series like “V” and “Falling Skies” (as well as movies like “Red Dawn,” though there the invaders were Commies), resistance continues. Though the older of the two Drummond boys from the opening prologue, Rafe (Jonathan Majors), is listed as deceased, a legendary hero of the movement, the younger, Gabriel (Ashton Sanders, failing to match the promise of his breakthrough roles in “Moonlight” and “The Equalizer 2”) survives, a surly subject of the government who works erasing the memory of digital devices that have been banned by the aliens.

Gabriel remains sufficiently opposed to the regime, however, to refuse cooperating with Mulligan—who as the onetime partner of the boy’s father, feels a sense of obligation to the kid—in helping to unmask the resistance’s leadership and mode of operation, even as the group is plotting an assassination attempt at a big “Unity Event” being staged at Soldiers Field, where the Bears are conspicuous by their absence. He rejects Mulligan’s entreaties even after Rafe proves to be still alive and captured (and tortured) by the cops.

What follows is a confused and slapdash affair as Mulligan, played by Goodman with a perpetually sleepy, world-weary attitude, works to ferret out the ring and prevent the aliens from wiping out a whole section of Chicago, the way they famously did a troublesome area called Wicker Park years earlier. Still, he occasionally takes time off from his official duties to visit a prostitute (Vera Farmiga), who gets her clients in the mood by playing a remarkably well-preserved LP of Nat “King” Cole’s “Stardust,” CDs apparently having gone the way of all “modern” things.

“Captive State” finishes up in a last act with a major revelation about the Drummond family’s past (related through some scratchy old video) and a complete explanation for the resistance’s schemes, though the payoff frankly comes like a bomb that fizzles rather than exploding.
Perhaps that’s the result of the movie’s low budget, which allows for some blink-and-you’ll-miss them alien effects (the rocklike spaceship streaking across the sky could probably have been improved by a twelve-year old at his computer, while the actual extraterrestrials look either like giant porcupines or armored versions of “Predator”). Chicago suffers desolation again, at least from a distance in faraway vistas; the actual street scenes, including the ones around Soldier Field, have just about the same visual finesse of the “Purge” series, shot by cinematographer Alex Disenhof in the drabbest shades of gray and blue.

Along with Farmiga a number of other well-known faces make fleeting appearances in the movie—Alan Ruck and D.B. Sweeney among them—but like her they’re wasted. (There’s also another rapper transitioning to acting—a fellow who uses the moniker Machine Gun Kelly, and was previously in the notorious “Bird Box”—but he merely proves he should stick to his main gig.) Wyatt, who pumped considerable energy into “Rise of the Planet of the Apes,” fails to repeat the trick here.

One might appreciate the effort to do something different on a modest budget, but ultimately “Captive State” resembles an elongated “Twilight Zone” episode with a twist ending that doesn’t quite come off. And it drags along so desultorily that watching it you might feel like a captive yourself.