Dan Kincaid was a deputy sheriff in Colorado, but when his teenage sister was brutally murdered by outlaw Matt Barton, he quit his job and went after the killer. His search took him to the Texas Panhandle Diamond B ranch owned by Matt's father, Isaac Barton, who ran the ranch with his second son Ron. The Diamond B Ranch was a front, and from it, once a year, Matt Barton led a band of men to steal cattle passing along the Western Cattle Trail.