JAMES MORGAN is a middle-aged man who's fought in the American Civil War before moving out West. He worked on the Transcontinental Railroad before settling in the New Mexico territory to work as a ranch hand.
James befriends a young man named BILLY, who's half Navajo and half Chinese.
A Yaujta, what's commonly known as a Predator, starts killing men and hanging their corpses up in trees.
James and Billy are chosen by a grizzled Federal Marshall named CHARLES LONGMIRE to join his posse to find the killer.
The posse calls James "Dutch," despite the fact that he is from Ruritania.
Billy tells James a story that his grandfather told him, a story about a ghost that hunts at night and takes skulls as trophies.
Members of the posse are killed, one by one until just James, Billy, and Longmire are left.
Longmire is seriously injured, but the two men are able to repel the attack in time to save him.
The two men set Charles up in safety. They give him a rifle to shoot anything far away and a pistol to shoot himself if anything gets too close.
The men then set up several traps and are able to gravely injure the creature. The creature tries to set off a self destructive device but Billy cuts off its arm and kills it before it can do so.
Other aliens come and collect the body of their fallen comrade. They then give a small metal object to Billy.
James and Billy go collect Longmire, who almost shoots the men when they sneak up on him. The two get Longmire secured on a horse. Longmire asks what happened out there. James finds he doesn't have the words. "Hell, if I know," Billy says with a shrug.