The Marshal sends John Weston to a rodeo to see if he can find out who is killing the rodeo riders who are about to win the prize money. Barton has organized the rodeo and plans to leave with all the prize money put up by the townspeople. When it appears that Weston will beat Barton's rider, he has his men prepare the same fate for him that befell the other riders.
A crazed scientist needs primates to conduct experiments to prove his own theory of evolution, so he organizes an expedition into the jungles of Borneo to capture the animals he needs.
Mary Brooks' father, who has been studying ancient tribes, falls into the hands of "the people of Zar, god of the Emerald Fingers." Tarzan helps Mary locate her father, rescues everyone from the High Priest of Zar, and takes Mary to his cave.
Easter, a soldier of fortune and gunrunner, leaves his family behind escaping from the authorities and an American detective named Mason. His globe hopping escape leads him finally to South America, where he is hired to organize a band of revolutionaries, unaware that they plan to eliminate him when his job is done.
A young lawyer is elected mayor of the city and promises to rid it of the corruption it's famous for. The problem is that most of the corruption he's vowed to eliminate is caused by the crooked political machine that helped elect him.
When Mark 'High Gear' Sherrod looses his nerve, the race car driver takes a job driving a taxi, but when he befriends a cute reporter and the young handicapped son of a deceased driver, he attempts to return to the track.
Four survivors of a ship wreck are stranded on a deserted island, including a woman and the man she believes is responsible for the murder which her brother is in prison for.
The villainous Dr. Fu Manchu races against a team of Englishmen to find the tomb of Ghengis Khan, because he wants to use the relics to cause an uprising in the East to wipe out the white race.
Kincade and Blake cause a mail plane carrying a payroll to make a forced landing in the desert. When they try to get the money, prospectors Ted and Si drive them away. With the pilot shot, Ted takes over as pilot figuring another attempt will be made and this time the Sheriff will be there.
Cowboy is hired by an archaeologist to help find "Hidden Valley", where an Indian gold treasure is supposed to be buried. Just when he finds it, the archaeologist is killed, and the cowboy his charged with his murder.
When legendary hunter Bob Rainsford is shipwrecked on the perilous reefs surrounding a mysterious island, he finds himself the guest of the reclusive and eccentric Count Zaroff. While he is very gracious at first, Zaroff eventually forces Rainsford and two other shipwreck survivors, brother and sister Eve and Martin Towbridge, to participate in a sadistic game of cat and mouse in which they are the prey and he is the hunter.
Dr. Robert Cromwell performs a delicate operation, that has never been done before, and the patient dies. Charged with malpractice and manslaughter, his trial is national news but the jury acquits him. But the court of public opinion is still against him, and the medical board is meeting to decide whether or not to take his medical license away from him. Before they do, Cromwell, an amateur pilot, decides to join his friend, WWI Ace Donald Evans, on a flight to Alaska looking for a shorter route to Japan by following the Aleutian Islands. They crash in Alaska and Evans is killed, but Cromwell is rescued by a fur trapper named Tom Ross. He takes Cromwell to Armstrong's Trading Post, where is is nursed back to health by Klondike, a girl who works for Armstrong, and was engaged to marry Armstrong's son Jim. The latter is suffering from the same disease that Cromwell's last patient had...
Steve Drexel voluntarily strands himself on a deserted island on a bet. He intends to re-create civilization and carves a miniature city of 52nd Street and Park Avenue out of the jungle. Drexel is befriended by his dog, a native monkey, and a wild goat that is captured in one of his traps. He attempts to cultivate a native as his Man Friday from Robinson Crusoe, but fails as the native escape.
When a young South Seas sailor falls overboard, the beautiful daughter of a Polynesian king dives in and saves his life. Thus begins the romance of Johnny and Luana. Though Luana is promised to another man, Johnny whisks her away, and for a brief time the lovers live very happily together. But, when a local volcano threatens their lives, Luana knows that she must sacrifice herself to the volcanic gods in order to save her island.
The Wrecker wrecks trains on the L & R Railroad. One of his victims is Larry Baker's father. Baker wants to find the evildoer, among a host of suspects, but it will be difficult since the Wrecker can disguise himself to look like almost anyone