After Cowlorado Kid was unable to catch a gold thief, he, Moo Montana, and Dakota Dude look for the thief and end up escorting a wagon train led by Rooster Cogsbull through a valley where a creature called the Cowgoyle (a cattle/gargoyle creature) dwells. To make sure that the C.O.W.-Boys meet their end and the Cowgoyle is blamed for the action, Mayor Bulloney sends Saddle Sore and Boot Hill Buzzard to get the Masked Bull to dispose of them. Following the Cowgoyle's attacks, the C.O.W.-Boys work to catch the Cowgoyle while suspecting that it might be one of the suspicious wagon train travelers.