After robbing a bank of $100,000 in gold bars, Dan Hogan, Klaus Kinski and his gang gather at the Jackal's Ranch stagecoach way station near the Mexican border, where Hogan's girlfriend Daisy, Anna Zinnemann, is supposed to quietly deliver the stolen loot. While they wait, a stranger named John Webb, Paolo Casella, who had shot the man who was to be their guide, arrives with a demand for half the gold in exchange for guiding them into Mexico. Webb hints that there may be a traitor in the group, stirring suspicion that even Daisy could be compromised. The gang also traps several travelers by imprisoning them on the station's stagecoach, turning the place into a tense holdout under a dull, sun-baked sky.
Reed, Dino Strano, one of Hogan's men, keeps everyone at gunpoint and destroys the telegraph, despite Hogan's protests. An attempt by Jonathan, Dante Maggio, the station owner, to intimidate Reed fails after Webb speaks up. After Daisy arrives, Hogan shoots Reed and offers Webb Reed's share, but Webb demands a full half, setting the stage for a fragile, uneasy alliance.
Rangers arrive, having realized the telegraph is out. The gang hastily hides themselves and their female hostages. The rangers depart, unaware of the trap, but tragedy follows when one of the gang members accidentally kills a woman during a failed rape attempt. A second gang member, disgusted, confronts him and the two end up killing each other. The coachman tries to persuade a passenger to kill Hogan, but when that plan fails, Hogan shoots the coachman and tensions inside the group rise.
At dawn, Webb leads the remaining gang members, including one of the women from the coach, and Sandy, Jonathan's granddaughter, into the desert. Jonathan informs the rangers about their likely route and sets off in pursuit in hopes of rescuing the women. The rangers catch up and their commander reveals a startling truth: Webb is Parker, the son of a famed judge who was killed along with his family by Hogan during the Civil War.
On the trail, members of the group die one by one. One of the women drowns in quicksand while Hogan watches, a grim reminder of the danger they all face. Mutual suspicion intensifies, and Hogan becomes separated from the others. After Cobra goes to search for him, the remaining members hold Webb and Sandy at gunpoint and force Webb to guide them to the border alone. They soon re-encounter Hogan and Cobra, and Hogan kills Cobra for deserting him. Before they reach the border, Webb releases Sandy, the final hostage, reminding Hogan that the traitor’s identity remains unknown to him, prompting Hogan to kill Cobra in a final display of paranoia.
Webb finally reveals his identity to Hogan, who grows more determined to destroy him. In a climactic confrontation, Webb shoots and kills Hogan. Webb retrieves Sandy and re-joins the rangers and Jonathan. He offers to let Sandy claim Hogan's body for the bounty, but instead she chooses to ride off with Webb, stepping into an uncertain but hopeful future.
