Jack McCall, the star of a traveling carnival show who is famous for his dazzling speed with a six-gun, longs for the freedom of the trail. Upon leaving the show, he quickly gains the friendship of former deputy sheriff Dakota Dan. One afternoon as the two shoot the breeze and sip their brews, they notice Curly McBride and his two friends, all hired guns of the power-hungry rancher Brad Barlow, cheating an honest Indian out of his money. Easily overtaking the trio, Jack humiliates the men and earns the trust and friendship of Chota, the Indian.

As Barlow's private army pursues Jack and his new friends across the desert, Jack knows he needs to find a hideout quickly. Luckily, Chota leads them to a secret village hidden in a subterranean world. Along the way, Jack rescues a beautiful Indian girl called Fawn who soon steals his heart.

Once inside the huge underground cavern that is home to Chota's people, Jack has to convince them that he can be trusted to keep the secret of the underground world before they can let him go back to the outside world. In order to do this, Jack must take on a demon known as Qualtari that lives in an underground river.

Jack is determined to get out of the river alive, not only to settle accounts with Brad Barlow, the revengeful rancher, but to win the heart of Fawn. But Qualtari sounds angry, and Jack is not allowed to take any weapons with him. Will Jack overtake his enemy—even without his pearl-handled Colt .45s?