The first singing cowboy of the screen made his starring debut in this 1935 serial. Gene Autry was an established singer by the time he got his first film role. The Phantom Empire was a Mascot production and combined a western with a musical with science fiction.
Autry stars as himself. Unlike most serials he has two sidekicks (most just had one). Frankie Darro and Betsy King Ross are junior riders (and foregoing child labour laws they did all their own stunts). Autry is a radio singing cowboy who owns a ranch where Darro and Ross hang out with their friends calling themselves The Junior Thunder Riders. The real Thunder Riders are a mythical group of riders who wore armour and when they ride the sound like thunder. It also turns out that the Thunder Riders are real and they kidnap Autry and the gang.
They are taken to the secret underground city of Murania. An ancient civilization that has advanced further than those living on the surface. They have robots, ray-guns and elevator tubes. Naturally they are ruled by an evil blonde Queen.
The stunts are amazing but the effects are cheap. The budget was less than 100,000 dollars. The movie catapulted Gene Autry into stardom and between 1935 to 1940 he made another 40 movies. From there he was replaced as top singing cowboy by upstart Roy Rogers. Still Autry had a long running radio and television show and is responsible for the songs “Here Comes Santa Claus” (which he wrote), “Frosty the Snowman,” and his biggest hit, “Rudolph the Red-Nosed Reindeer.”