A 12 chapter Mascot serial that pits singing cowboy Gene Autry against a super-science underground civilization. The plot is as deliriously absurd as it sounds. The production values are surprisingly good. Wacky fun from beginning to end. It's available here at IA in the Short Format Films Collection (shorts).
a.k.a. "Gene Autry and the Phantom Empire"
TRIVIA: The robot suits were originally made for "Dancing Lady" (1932) but their scene was cut. Happily they survived to show up here and again in the 1951 serial "Captain Video, Master of the Stratosphere," the trailer for which is in this collection.