Fur thieves, who murder trappers when they refuse to give up their pelts at a low price, occupy the attention of the Royal Northwest Mounted Police. The leader of the gang is Victor Renaud, also the mayor of the small Canadian town where the gang is headquartered. Lucky Kerrigan is broken from the mounted service for apparent disobedience to orders, which results in the death of a fellow Mountie. Lucky, working undercover, aids the Mounties in rounding up the gang and gains back his uniform, and also the love of Gabrielle Renaud, Renaud's sister who was unaware of his criminal activities.

The story opens as Stony returns to his home town, only to discover that his sheriff father has been murdered by person or persons unknown. The new sheriff (Henry Brandon) resents the arrival of the Mesquiteers, going so far as to frame Tucson on a murder charge.

Krag Sabine has aroused the wrath of all the ranchers by stealing their land with the aid of his henchmen, led by Ace Barco; when Lafe Martin objects, the outlaws shoot him down. Lucky Randall promises Ann Martin he will avenge her wounded father. He sets up headquarters on the Martin ranch and sends for Bob Merritt and his men, the Texas Playboys (Jesse Ashlock, Leon McAuliffe, Cotton Thompson, Junior Barnard and Luke Wills). Krag organizes his remaining men for an attack on the ranch. Lucky's men get the upper hand but Krag escapes with Ann as his hostage.

When Tasker kills Roy Rogers he takes one of his young sons. Fifteen years later the other son Roy arrives buying a ranch in the valley where Tasker now controls the water supply. Roy organizes the ranchers for a showdown with Tasker not knowing that his brother is Tasker's chief henchman.

A famous scientist invents a humanoid robot (the titular "monster"), so a greedy rival scientist plans to steal it for use in his criminal plans. His henchmen often kidnap a trained gorilla (the titular "ape") from the zoo, to aid in the schemes.

Columbia's 33rd serial (made between "Jack Armstrong" and "The Sea Hound") was based on the character that first appeared in "Action Comics" No. 42.

Billy the Kid is framed for murder.

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.

Superman battles Lex Luthor, who is using a teleportation device and a new identity as Atom Man in his criminal plans.

Tom Kenyon and his sidekick Pierre La Farge are hired by rancher Mike O'Day who, with his daughters Toni and Sugar, provides wild horses for the government remount station.