The Range Busters are at it again in Monogram's Underground Rustlers. Set in California gold country during the financial panic of 1869, the story concerns a gang of clever gold thieves who utilize a subterranean tunnel to abscond with their ill-gotten gains. Enter our three heroes, Ray "Crash" Corrigan, John "Dusty" King and Max "Alibi" Terhune. After much bantering byplay and a few songs courtesy of Mr. King, the Range Busters begin busting heads for a change, the better to bring the villains to heel. Surprisingly, Underground Rustlers is virtually bereft of action, promising much but delivering little.