One of the meanest and most dangerous animals in the United States is the buffalo bull. He's a savage fighter, always walking around with a chip on his shoulder. He attacks without warning, and moves like a bolt of lightning. The rangers never get close to the buffalo herd unless they're riding fast and experienced horses. Each herd has one bull who's the big boss, and when he gets old and loses some of his speed and fighting ability, one of the younger bulls will challenge the big boss. A fight follows, and the older animal is run out of the herd. The dethroned bull becomes a lone marauder, venting his humiliation and anger with savagery upon any living man or beast. So now it's time to join Bill and the rangers as they hunt 'the mad bison'...