Dr. John Meredith has been driven from civilization by the criminal activities of his twin brother Bradley Meredith. With his infant daughter, he settles in the African jungle, where his ability to cure the native ills has resulted in his virtual control of the Masamba tribes, who possess vast diamond mines coveted by a gang of crooks. They use Shamba, a witch doctor jealous of Dr. Meredith's influence over the tribe, to further their schemes. They lure Dr. Meredith away from the jungle, and he is murdered by "Slick" Latimer. The natives believe that a sacred amulet is the secret of Dr. Meredith's power, and Shamba attempts to kill Nyoka, Meredith's now-grown-up daughter, to obtain the amulet (which actually contains the secret to the entrance of the Caves of Nakros). Jack Stanton rescues her and assists her in her efforts to recover the amulet. Latimer works with Shamba, and with Bradley Meredith, who poses as his murdered-brother so successfully that even Nyoka does not realize the deception.

American, British and Chinese secret agents battle the Japanese Black Dragon Society, a secretive ring that smuggles enemy agents into the U.S. disguised as mummies.

Alan Armstrong, aka Spy Smasher, battles a Nazi villain known as The Mask, who heads a gang of saboteurs determined to spread destruction across America.

Mountie sergeant and his three constables find themselves facing multiple perils at the hands of an outlaw gang which, aided by a corrupt Indian medicine man and his followers, have brought a halt to construction of a key railroad line through the Canadian Northwest.

It's intrepid Nyoka and her friends versus Vultura, Queen of the Desert, on a quest for the Golden Tablets of Hippocrates.

An American secret agent travels to Africa to infiltrate a Nazi spy ring.

Girl looking for father who disappeared years before in a jungle, finds herself battling greedy civilized people and savages alike.

Filmed in the Sierra Nevada mountains near Sonora, California, this Universal serial is Universal's 40th sound-era serial. Eagle Scout Bruce Scott, leader of Martinsville Troop Number One, and his pack sets off in search of lost treasure and finds adventure.

A famous detective sets out to discover who stole $2 million in bonds.

A young radio cop and a beautiful girl try to stop an international criminal gang from getting their hands on the formula for a new bulletproof steel.

A scientist invents a poison gas; the villain and his gang will do anything to get the formula; our hero, "Lightning Hutch", is sent to save the scientist, the scientist's beautiful daughter, and the formula.