Prof. Gibbs accidently uncovers some ancient Indian writing in a cliff dwelling that mentions treasure. Accompanied by Rex and several other patrons of a trading post, they set out for the "Fortress of the Cat" However, two of the group are escaped convicts, who have their own plans.; Trigger Larson plans an perfect alibi by using a partner whose voice sounds the same as his to stay in a bathhouse while Larson robs a stage.; A prospector doctors a map to fool two claim jumpers who want to steal his gold mine.