The protagonist, who is later revealed to be named Jake Lonergan, wakes up in the desert with no memory of who he is or how he got there, but with a strange metallic bracelet around his wrist. He wanders into Absolution, a small town in Arizona, where he quickly finds trouble. Sheriff Taggart recognizes him as a wanted criminal and prepares to arrest him, but before he can do so, aliens begin attacking the town.
The aliens have been abducting people from the town for several years, including Ella's husband and Dolarhyde's son. Jake's bracelet turns out to be a highly advanced weapon that can destroy the alien ships. Together with Ella, a beautiful and mysterious woman who has also lost someone to the aliens, and Dolarhyde, a wealthy and powerful landowner, Jake leads a group of cowboys and Native Americans in a mission to rescue the abducted townspeople and stop the aliens.
As they travel through the desert, the group faces many obstacles, including a group of bandits led by a former acquaintance of Jake's named Doc. They also discover that the aliens have been using human captives to help them mine for gold, which they need to power their technology. Jake and Ella connect over their shared losses and growing feelings for each other, while Dolarhyde learns to trust Jake and work with the Native Americans he had previously treated with disrespect.
In the final battle, Jake and the others face the alien queen and her ship, using all their skills and weapons to defeat her. In the aftermath, Jake decides to leave Absolution and continue his journey to discover his true identity, while Ella decides to stay behind and help rebuild the town. Dolarhyde and the other survivors return to their lives, forever changed by the alien invasion they had faced.