The Great Gold Robbery, Parts 3 & 4 / Mesa Mess (Go Go Gophers) / Niagara Falls (Commander McBragg)

Underdog is still confused and frustrated trying to find Sweet Polly among all the balloon; The train full of gold is about to crash into another train, with Riff-Raff's plan going just as he expected; The Colonel leads an assault on the Gophers' secret hideout atop Lonesome Mesa - unaware that the mesa is a Gopher construct laden with traps; Commander McBragg tells a tale that happened at Niagara Falls