The Phantom Empire is the greatest serial ever made.  It runs for 245 minutes, and footage from this serial was edited down to 70 minutes in order to make a movie out of it, alternatively titled Radio Ranch or Men with Steel Faces.  The movie version loses much of the camp value of the serial, however.  Also lost is the way it cheats with the cliffhangers, letting us think something terrible happened, only to show something different at the beginning of the next chapter.  Subsequent chapters after the first begin with a stirring piece of music that sounds almost too good to be original with this serial.

Gene Autry, playing himself, is half-owner of Radio Ranch, where people come to stay as paying guests and from which Autry broadcasts a radio program every day.  In the first chapter, after singing a song, he introduces Frankie Baxter (Frankie Darro) and his sister Betsy Baxter (Betsy King Ross), his partner’s children, who head a club sponsored by Radio Ranch called National Thunder Riders or Junior Thunder Riders.  They tell about how one day they saw a bunch of men with capes and helmets riding horses that sounded like thunder, though they do not know who those men were.  Nevertheless, Frankie and Betsy formed the club, the members of which wear capes and helmets modeled after the ones worn by the original Thunder Riders, as they call them.  Other kids are encouraged to visit the ranch and join the club, or they can start their own local fan club and get patterns so that their mothers can make Thunder Rider costumes for them.

Then Autry narrates the next installment of a serial within this serial in which the Junior Thunder Riders ride to the rescue to save a man and his wife from a bunch of bandits.  You might think that since this is a radio serial, only dialogue and sound effects would be involved, but they actually act out the parts, almost as if it were being filmed, which, I guess, in a way it is.  Perhaps not so much anymore, but there was a time when children would see a Western at a theater on Saturday morning and then want to play cowboys and Indians that afternoon.  This serial took that one step further by having the children within the story playing at what the grownups were doing, even to the point of becoming involved with the grownup story itself, thereby making it easier for the children in the audience to imagine they were part of the story when they acted out the parts later on.

Meanwhile, a bunch of men fly in by airplane, who we quickly figure are up to no good.  One of them, Professor Beetson, believes that somewhere underneath Radio Ranch is Murania, populated by descendants of an ancient city, who moved underground to escape the glaciers a hundred thousand years ago.  Beetson believes that if they can locate Murania, they will find valuable deposits of radium and secrets that have been lost to the world, technology based on their knowledge of radiation.  Their plan is to get rid of Autry by causing him to miss a broadcast, which will result in the loss of his radio contract.  Or they can just kill him.  Either way, they figure the ranch will become deserted, giving them the freedom to look for Murania without being disturbed.  This plot point leads to several ludicrous situations in which Autry is fleeing from the Thunder Riders or from the scientists, in danger of losing his life, and right in the middle of it all has to worry about getting back to the ranch in time to sing another song.

All this is on the surface.  Meanwhile, twenty-five thousand feet below the ranch is Murania, where the original Thunder Riders live, when they are not galloping about on the surface for whatever reason.  There are, of course, the expected absurdities in this lost city, such as that everyone speaks English.  Muranians cannot breathe surface air, so they have to wear helmets that supply them with oxygen whenever they leave their city.  (Don’t look at me, that’s the explanation that is given.)  And yet, although Muranians cannot breathe surface air, surface people have no trouble breathing Muranian air.  Also peculiar is the mixture of ancient and futuristic technology.  The Muranians have television, allowing their ruler, Queen Tika, to see and hear what is going on anywhere on the planet.  They have all sorts of advanced weaponry, such as guided missiles and ray guns, and yet the guards carry spears.  They have robots to perform the manual labor, but the ones that are armed have swords.  Moreover, when the Thunder Riders need to enter or leave Murania, they have a robot turn a crank to open the door, instead of simply having the equivalent of a garage-door opener.

Their government seems to be a bit of a mixture as well.  As noted, there is a queen who rules over her subjects.  However, she refers to one of the wounded soldiers as a “comrade,” a term not normally used in monarchies, but which would have suggested a communist state like the Soviet Union in 1935.  And there is reference to the “secret police.”  When she watches the television to see what is going on in the world, she is contemptuous of the insanity she witnesses, calling the surface people fools, who are always in a hurry, their lives full of death and suffering.  You might think from this that Murania must be an enlightened utopia, especially when she declares that their civilization is not only advanced, but also serene.  But when the captain of the Thunder Riders fails to capture Autry as she commanded, she starts to put him to death for incompetence, but then decides that lashes with a whip will be a better punishment.  In fact, she routinely condemns her officers to the “Death Chamber,” after which their charred bodies are sent to the “Cavern of Doom,” so we wonder just how serene her subjects can be under the circumstances.  She wants Autry captured so that she can drive everyone off Radio Ranch, because she fears that surface people will discover Murania and invade it.  Of course, it is Autry’s very presence at Radio Ranch that is preventing the discovery of Murania by Beetson and others, as she well knows from watching that television of hers, which allows her to overhear Beetson discussing his plans.  But she figures on getting rid of Autry’s Radio Ranch first, Beetson’s gang later.

When the captain fails a second time, she commands Lord Argo to put him to death in the Lightening Chamber.  But once inside, Argo tells the captain that every time someone is supposedly put to death (thirty-seven so far this year), he saves him so he can be part of the rebellion he is planning.  The captain agrees to join the rebellion, and so his execution is faked.  Though Queen Tika has people whipped or executed for merely failing to carry out her orders, despite their best efforts, yet when she finds out about the rebellion, she cannot understand why people are turning against her.  After all, she knows she has been a good queen, because that is what her underlings tell her when they are asked.  Later, Betsy says what most of us have been thinking, that Queen Tika reminds us of the one in Alice in Wonderland, always shouting, “Off with his head.”

Meanwhile, back at the ranch, the Junior Thunder Riders have parallels to Murania beyond merely fashioning themselves after the Muranian Thunder Riders.  Frankie has a secret laboratory on the second floor of a barn in which he invents gadgets, just as scientists in Murania continue to develop new technology down below.  While the Muranians have wireless telephones, the Junior Thunder Riders can be summoned to the secret laboratory with a light bulb moving up through the roof blinking on and off in Morse code.  While the Muranians below the surface watch the world on their television, the Junior Thunder Riders watch what is happening on Radio Ranch with a periscope that peeps through that same hole.  And just as the Muranians live secretly underground, the Junior Thunder Riders have a secret underground passageway beneath the barn leading out of the side of a hill much as the entrance to Murania is on the side of a mountain.  Just as we see only one female in Murania, Queen Tika, so too is there only one female in the Junior Thunder Riders, Betsy.  In one sense, however, the parallel is one of contrast:  while the Junior Thunder Riders consist only of children, the Muranians seem to consist only of adults.  Of course, that might make sense if the Queen is the only woman in the place.  In any event, she refers to Frankie and Betsy as “undeveloped surface creatures,” almost as if the very idea of children is one unfamiliar to Muranians.

And just because these are not enough plot complications, Autry is framed by the scientists for killing his partner, and so in addition to being hunted by Beetson’s gang and the Muranian Thunder Riders, he is also being pursued by the sheriff, all of which makes that daily broadcast a bit challenging.  Fortunately, he has the Junior Thunder Riders to help him in that regard.

Eventually, Autry is captured and brought to Murania, but he escapes.  Later, Frankie and Betsy are captured and brought to Murania, but then they escape too.  To block the path of anyone not authorized to pass by, there is a robot standing off to the side with a sword held erect.  When activated by a button on its chest, an infraray tells it if someone is trying to pass, at which point it comes down repeatedly with its sword.  So, when Frankie and Betsy are trying to escape and are blocked by that robot, Frankie presses the off button on the robot’s chest, and then they go right past it without a problem.

The rebels do not intend to establish a democracy, but rather simply want power, which promises to result in an even more repressive society than the one run by the queen.  As a result, Autry and his friends team up with the queen, who aids them in their escape.  However, in the course of the rebellion, all of Murania is wiped out by the latest advance in weaponry, an atom smasher capable of destroying the entire universe, but which ends up destroying itself instead.

Back on the surface, Beetson confesses to killing Autry’s partner, daring Autry to try to prove it.  However, thanks to a piece of equipment Frankie brought back from Murania, the confession is caught on television, and the bad guys are arrested, after which Autry makes it back to the ranch in time for his final broadcast for the season.