A none-too-popular (nor good) radio singer, Rita Wilson is murdered while singing on the air in a radio studio. Radio page boy, Frankie Ryan, and his janitor pal, Jeff, solve the mystery for the none-too-sharp police.

Rodeo star Roy Rogers (Roy Rogers), returning with his horse "Trigger" to his home town, finds old Tom Craig (Leyland Hodgson) murdered and offers his aid to "acting sheriff" Gabby Whittaker (George Hayes). Roy meets Helen Williams (Dale Evans), new singer at the Trading Post club, who is on her way to see Craig about a family-heirloom crest which he has stolen from her father. Arthur Courtney (Douglass Dumbrille)is informed by his henchmen that Craig is dead but they were unable to find the crest since Gabby, Helen and Roy had appeared on the scene. He orders them to get rid of Roy and Helen. After narrowly missing being killed while on their way to an Indian pow-wow, Roy and Gabby go to the Craig ranch where they discover an old clock and the crest hidden it it. They are taken captive by Courtney's henchmen and watch Courtney press a catch on the crest and take out a piece of paper. A fight ensues and The Sons of the Pioneers (Bob Nolan, Tim Spencer, Hugh Farr, Karl Farr and "Shug" Fisher) and Roy's Indian friends come to Roy's and Gabby's aid.

During WWII, the German Navy created the world's first stealth submarine, the U-480. A thin layer of rubber was added to it's skin to defeat the British sonar known as ASDIC. The sub went on 3 patrols, sinking 4 ships and shooting down an aircraft. In 1945 the sub was sunk and all hands were lost, except 1 who was left behind for training. During it's career, U-480 was never detected by Allied sonar.

In 1763, felon Abby Hale is sentenced to slavery in America. In Virginia, heroic Capt. Holden buys her, intending to free her, but villain Garth foils this plan, and Abby toils at Dave Bone's tavern. Garth is fomenting an Indian uprising to clear the wilderness of settlers, giving him a monopoly of the fur trade. Holden discovers Garth's treachery, but cannot prove anything against him. Can Holden and Abby save Fort Pitt from the Senecas? Many hairbreadth escapes.

Adventure-seeker Ted Osborne has convinced his finacee Carole to finance his expedition to an uncharted South Pacific island supposedly populated with dinosaurs. Piloting their ship is Captain Tarnowski, a ruthless alcoholic suffering from malaria- induced bouts of insanity. When they arrive at the island, they discover that the stories they have heard are all true. Will they survive to tell anyone what they've found?

A newspaper reporter and the daughter of an immigrant maintenance man help expose political corruption in New York City.

Gold stages are being held up in the far west at a time when the U.S. government needs bullion, just before the famed "Black Friday" attempt to corner the gold market. The government sends the Range Busters, Crash Corrigan, Dusty King and Alibi Terhune, to Gold Butte, an important bullion dispensing center, to put an end to the stage robberies.

Roy has just finished his latest film and leaves for his ranch where he will be broadcasting a show celebrating his tenth year in movies. When Roy and Trigger arrive at his ranch he finds Cookie has hired his relatives. Caroline, the only relative that doesn't have a strong resemblance to Cookie, is the horse trainer. Bob Tells Roy a gang of men are hunting range horses. Roy puts a stop to hunting on his land. Pop decides there's money in kidnapping Trigger and demands a $100,000 ransom. McFarland's stepson, Ted, and his dog Tramp, run away and is found hiding in Roy's barn. A trap is set to catch the kidnappers ranch.

Secretary Joyce Willecombe grows suspicious of two men boarding her train and is referred to 'Tough Willy' Calhoun, head of the Union Station police. The all-seeing, no-nonsense Calhoun is initially skeptical, but the men (who escape) prove to be involved in a kidnap case. Calhoun calls in equally tough police Inspector Donnelly, but the ruthless kidnapper's precision planning stays one jump ahead of them. Most of the action centers around bustling Union Station.

Young bride Ann Hamilton soon begins to suspect that her charming husband is really a psychotic who plans to murder her.