When Dude Cottrell, gambler, and his pal, Omaha, tried to make prospector John Weaver tell them where his secret gold mine was, Weaver refused and was shot down. Keno, the prospector's dog was also shot and wounded. Subsequently, Keno went on a search for the men who had killed his master, and in town came across Dude and Omaha at a time when Weaver's niece Malinda has just arrived from the East. A cry of "mad dog" goes up as Keno charges Dude. Cisco prevents Dude from killing the dog, and subsequently, he and Pancho nurse Keno back to health.