John Wayne

Lucile Browne

George 'Gabby' Hayes

LeRoy Mason

Lloyd Ingraham

John Martin is a government agent working under cover. Leading citizen Morgan calls in gunman Galt who blows Martin's cover.

Johnny Mack Brown and Raymond Hatton return to the screen as saddle pals Nevada and Sandy in Monogram's Pals of the Border. In this one, our heroes are US marshals, hot on the trail of cattle rustlers.

Cowboy star Ken Maynard is Jim "Trigger" Morton, in town undercover while pursuing the man who framed him for robbery. But a well-placed shot tames a band of scofflaws and gains Morton the sheriff's badge. Now, he's riding on both sides of the law. The line is further blurred when old buddy Chuck offers evidence of Morton's innocence in exchange for a blind eye to Chuck's impending postal heist in this classic Western.

Hoppy goes undercover as a gambler from the East when Bar 20 cattle are stolen by unknown rustlers. Brennan/Talbot are twin brothers (one a casino owner, the other a rancher) and Hoppy believes they provide alibis for each other while one is out committing crimes. Hoppy gets a job in the casino to learn more but is exposed when a gambling gunslinger notices him.

Bill Tracy is a Cattleman's Protective Association agent. Working undercover on his way to Sonora, a town dominated by rustlers, saves Betty Carter from a situation, but her rancher father, believing Blackie's suggestion that Bill is a rustler, forbids her to see him. Bill and his pal Heinie Schmaltz rescue each other from rustlers' various plots and ambushes and eventually discover that Blackie, Carter's foreman, is the leader of the rustlers.

Major Lex Kearney, dishonourably discharged from the army for cowardice in battle, volunteers to go undercover to try to prevent raids against shipments of horses desperately needed for the Union war effort. Falling in with the gang of jayhawkers and Confederate soldiers who have been conducting the raids, he gradually gains their trust and is put in a position where he can discover who has been giving them secret information revealing the routes of the horse shipments.

Summarily accused of murder, drifters Duke (Foran), Pancho (Carrillo) and Andy (Devine) are tossed into the hoosegow, only to be released when their alibi checks out. Far from offended by his ill treatment, Duke agrees to take the job of sheriff, retaining Pancho and Andy as his deputies. The gruesome threesome then sets about to solve a series of mysterious Wells Fargo robberies

Tex Weaver is working under cover to bring in a gang of bank robbers. When he is killed, Tim Ross, a marksman with Doc Shaw's traveling show, takes over. Posing as a Mexican he lays a trap for the gang.

A reporter goes undercover to break up an outlaw gang.