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. Dude and Omaha try to bushwack Cisco and Pancho, and when Keno trails the bushwackers to Dude's office, Cisco decides there is more in the situation than meets the eye. Keno leads Cisco and Pancho to Weaver's mine. 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 had discovered the gold and slain his pal, Omaha, planning to blow them up with dynamite and ma