When gambler Dude Cottrell 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. Keno went on a search for the men who killed his master and came across Dude and Omaha in town at a time when Weaver's niece Malinda arrives from the East. A cry of "mad dog" goes up as Keno charges Dude. Cisco prevents Dude from killing the dog, and he and Pancho nurse Keno back to health. Dude and Omaha try to bushwack Cisco and Pancho, and when Keno trails the bushwackers to Dude's office, Cisco decides there is more to the situation than meets the eye. Keno leads Cisco and Pancho to Weaver's mine, where they find the slain prospector, and in turn are trapped by Dude and Omaha. Cisco and Pancho are left bound in Weaver's shack, with Dude, who has discovered the gold and slain his pal, Omaha, planning to blow them all up with dynamite and make it look like an accident. Keno, however, frees Cisco and Pancho and then gets Dude.