In the arid landscape of 1873 New Mexico Territory, a mysterious stranger awakens in the harsh desert, his left wrist encircled with an enigmatic metal bracelet. With his memories clouded in mystery, he stumbles into the dusty town of Absolution, where Preacher Meacham offers his care with a gentle touch. However, Sheriff John Taggart only sees a wanted outlaw — Jake Lonergan — and makes a move to apprehend him. Just in time, Ella Swenson, an enigmatic traveler, intervenes, disrupting Taggart's plans.
As tensions heighten, Colonel Woodrow Dolarhyde, the domineering father of Percy, arrives with a group of armed men, demanding that Jake be captured for allegedly stealing gold from him. In the thick of this standoff, an otherworldly menace descends upon Absolution: alien spacecraft arrive, snatching unsuspecting townsfolk, including Percy and Taggart, into their clutches. In a moment of unexpected instinct, Jake's bracelet transforms into a weapon, allowing him to shoot down a ship and repel the alien attack.
Regrouping amidst the chaos, Dolarhyde, Ella, and the remaining residents form an ad-hoc posse to pursue an injured alien that evaded capture. Meanwhile, Jake starts to unravel his past, remembering a fateful return to an abandoned cabin with purloined gold, only to be abducted by the same extraterrestrial beings alongside a woman named Alice. As memories come flooding back, Jake feels a newfound purpose and joins the party.
That night, the group uncovers a capsized paddle wheel steamboat, abandoned far from any major waterways. They seek refuge within its deteriorating walls, only to witness the brutal murder of Preacher Meacham at the hands of an alien, who sacrifices himself to protect Emmett, the innocent grandson of Taggart.
As dawn breaks, most of the posse has abandoned their leader, leading to a bitter confrontation between Jake and his former gang. The aliens wave in again, abducting Ella and making her a target for attack. Seizing the opportunity, Jake boards an alien ship and engages in a hard-fought battle against its pilot. As the ship crashes into a river, the pilot survives, but falls victim to Jake's wrist-blaster, avenging Ella's mortal injury.
Captured once more, the remaining posse members find themselves in the hands of the Chiricahua Apache, who harbor resentment and confusion for the calamity brought upon them. Amidst this turmoil, Ella's lifeless form is tossed onto a pyre by an ardent warrior, only for her to rise anew from the flames, eyes glimmering with an unearthly glow. She reveals a profound truth: her people, victims of the same alien invaders, traveled across the cosmos to aid humanity in its critical struggle.
The extraterrestrial assailants, equipped with superior technology and seemingly impervious to harm, have laid waste to human settlements and abducted innocents for nefarious purposes. Only Jake's trusty wrist-mounted weapon can end their monstrous reign. Ella's revelations spark a flame of resolve within the posse; they must eradicate this interstellar menace before all life on Earth is snuffed out like candles in a storm.
As Jake's mental fog dissipates, aided by the herbal remedies of the Apache medicine man, he confronts the horrors of witnessing Alice's brutal fate at the hands of the aliens, which strengthens his resolve to strike against the enemy. The location of the aliens' mothership now etched in his mind compels them to devise a strategy for battle.
Jake sets out to rally his former gang while Dolarhyde commands a coalition of posse members and Apache allies. A fierce ground battle ensues, ensnaring the aliens within a storm of bullets and arrows, as Jake and Ella penetrate the mothership to rescue captives, though Jake himself becomes a prisoner.
In a timely act, Dolarhyde rescues Jake from his alien captors, and together they seek vengeance against the creature responsible for Alice's gruesome demise. As the damaged mothership takes flight, the remaining aliens retreat, leaving chaos in their wake. However, Ella decides to stay behind, making the ultimate sacrifice that transforms Jake's wrist weapon into a bomb, obliterating the fleeing vessel and silencing the alien threat once and for all.
With the extraterrestrial menace extinguished, the townsfolk begin to rekindle their lives from the ashes of their grief. Despite still being a fugitive, Jake Lonergan chooses to abscond from his past troubles, with Sheriff Taggart and Dolarhyde concocting a cover to shield his involvement in the invasion. The rescued townspeople set forth on a path to rebuild, using the gold plundered from the aliens, envisioning a new life amidst the remnants of their beleaguered town.
