A man parks his car and peers into the vast Grand Canyon with binoculars, only to have the vehicle released by an unseen hand and roll toward him. He dives away at the last moment, and in a brutal struggle the attacker is knocked over the rim to his death.
Later, Eli Jones, a disheveled old prospector known for spinning tall tales, discovers the body and reports what he saw to deputy sheriff Martin, Cornel Wilde. But Martin—skeptical of Eli’s reputation—chooses to chase an attractive woman, Janice Kendon, Victoria Shaw, who is driving recklessly down the road. Eli finds the dead man again, this time hanging with his hands bound behind his back, and the mystery deepens.
The deputy and Janice soon team up to solve the murders. Janice provides a vital clue when she identifies the hanged man’s suit jacket as coming from an exclusive New York City tailor, revealing that the victim was an Eastern executive of a mining company who had traveled cross-country to Arizona to investigate possible theft. The case widens from a single assault into a potential corporate crime, and the tension grows as the trail leads through money, greed, and danger.
Meanwhile, Eli becomes the murderer's next victim, stabbed to death by someone he had welcomed into his home as a friend, a chilling reminder that the killer is not just elusive but personally calculating.
Janice’s brother Bob Kendon, a rich wastrel, spends most of his days at Scotty O'Brien’s tavern, the town’s lone local drinking spot. Janice follows a mysterious phone call to him, with Martin in tow, and their investigation tightens around Scotty O’Brien, Mickey Shaughnessy, who plays a central role in the darker side of the town’s operations. It turns out that O’Brien has been illegally siphoning gold from a closed mine and intends to fly Bob to Las Vegas in a private plane to help him pull off the scheme. When Bob uncovers the murders, O’Brien kills him just as Janice drives up, escalating the stakes and forcing the remaining characters to confront the danger head-on.
O’Brien then seizes Janice, driving her car and firing on Martin’s patrol vehicle, believing he has escaped surveillance. Yet the local authorities are keeping a close eye on him, with helicopter patrols tracking his every move. The chase culminates when Martin boards a cable car that spans the canyon’s deepest point. He and O’Brien end up in a brutal struggle on the outside of the car, and O’Brien plummets to his death as Martin rescues Janice. In the aftermath, the pair are left to reckon with the truth of what happened and the price of the pursuit of profit and power, with a cautious sense of relief that justice has been served, even as the landscape around them remains as unyielding and immense as the canyon itself.
