After exacting revenge on a pack of rustlers who made off with his green-broke mustangs, loner Yakima Henry returns home to find the delectable Faith, a soiled dove he once rescued. Her brother's landed in a Mexican prison—and Faith begs Yakima to guide her party down to rescue him. Yakima's never been able to say no to her, and soon finds himself in Mexico's Sierra Olivadas, fending off deadly Apaches and scalp-hunting Rurales led by a sadistic capitán and a beautiful revolucionaria, Leonora Domingo...

Having to shoot his way out of Mexico was the last thing Yakima wanted, but with the help of the lovely Leonora, her notorious Gatling, and an underground river in the Sierra, he and his yanquí posse will have to do just that...