Bad guys plot to trick a newly arrived Eastern girl out of a ranch which belongs to her infant ward. Roy, of course, saves the ranch for the girl. Songs include "I'm Headin's for the Home Corral," "He's a No Good Son of a Gun," "Sandman Lullaby," "Song of the San Joaquin," and "I'm a Cowboy Rockefeller."
A Nazi spy ring is after a chemical formula that increases the power of ordinary gasoline for U.S. Army aviation use. Two U.S. chemical companies are developing the formula, with each working on half for security purposes. The spies get half the formula and know that either of two chemists, Robert Norton or Tom Fielding, knows the rest. They capture Fielding, through a ruse by gang member Linda Pavlo, and threaten the life of his sister Nancy and his mother if he does not give them the formula. To protect his friend Fielding, who does know the formula and is engaged to Nancy, Tom pretends to know the secret and boards the Dawn Express plane with the spy leader and his gang.
After The Daily Planet receives a letter from a mad scientist threatening to wreak destruction with his Electrothanasia Ray, Lois Lane heads out in the hopes of getting more information for a news story.
The story concentrated on a group of test pilots, busily experimenting with a revolutionary all-plastic airplane. Ace flyboy Brad Farrell (Richard Arlen) is determined to prove the practicality of the new aircraft, designed by Professor Blake (Thomas Ross), father of Brad's sweetheart Carol (Jean Parker). Back on solid ground, Brad must vie for Carol's attentions with his own brother, engineer Doug Farrell (Don Castle).
When the showboat hits town, two men use the parade as a distraction to rob the bank. Their accomplice is Pop, the clown from the showboat. He leaves the money on the boat and tells his daughter Patsy to bring it to him at a later stop on the river. Gene's investigation of a bank robbery takes him to the showboat where he becomes a performer. Gene and Frog try to find the money while helping Patsy and her father.
Rightful owner of the kingdom, the Duchess of Zona, is engaged in a power struggle with the evil General Gurko. Edmond, the son of Monte Cristo, dons many disguises to come to the aid of the Duchess.
Bill Hickok, assisted by Calamity Jane, is after a foreign agent and his guerrilla band who are trying to take over some western territory just as the Civil War is coming to a close.
Trouble in Colorado is tying up Union troops needed back east during the Civil War and Lieut. Burke is sent to investigate. Macklin and his gang are causing the problems and Capt. Mason joins them. When Burke catches up with them he also finds Mason, his brother.
While Sam Houston in in the nation's capital trying to get Texas into the Union, his aide is trying to impose a self-serving tax on the use of the Santa Fe trail. The lady owner of a wagon train is using the trail, and a Texas Ranger comes to her assistance.
In and around some great blues, swing and jazz music, a very unpopular band-leader. Prince Ellis, is killed in a Harlem nightclub, and, in and around some more great music, a detective finds the lists of suspects is very long, as Prince Ellis was indeed very unpopular with many citizens.
The mysterious Don Del Oro ("Lord of Gold"), an idol of the Yaqui Indians, plans to take over the gold and become Emperor. Francisco was put in charge of a legion to combat the Yaqui tribe and protect the land, but when attacked Zorro came to his rescue. Francisco's partner recognized Zorro as the hidalgo Don Diego Vega, then ask him to take over the fighting legion as his alter-ego Zorro.