Las de sa vie de hors la loi, John Abbott revient dans les régions désertiques qui l'on vu naître.Il se lie d'amitié avec le rancher Andrew Naab et son fils , David. La fille de Naad, Myriam, tombe immédiatement amoureuse de ce bel étarnger ténébreux, bien qu'elle doive se marier au rancher Thornton pour honorer une promesse faite par son père.Mais le jour des noces elle est enlevée par Henry Holderness, un vagabond.John, les Naab, et les ranchers des environs se lance à sa poursuite.
Hoppy (William Boyd) and his pals must journey to Mexico after receiving a summons. Upon arrival, they realize that it was fake and that a good friend has been mysteriously murdered. They solve the puzzle with the assistance of the killer's feisty sister and a band of helpful caballeros.
Hoppy William Boyd) and his pal Lucky (Russell Hayden) head to South America to look after a herd of cattle sold by Cassidy's boss to an Argentine rancher. Villain Ralph Merritt (Sidney Blackmer) wants to get his mitts on that cattle, and he's not above hiring the scum of the earth to do his bidding. Fortunately, Hoppy, Lucky and their new Latino buddy Fernando (Sidney Toler) make short work of the bad guys in an outsized barroom brawl.
Hopalong Cassidy's Brother, Buddy, is shot in the back by the Deputy Sheriff Plunkett. His friend lucky tries to testify against Plunkett but is thwarted by the crooked coroner Stoneham.
Lorna Drake (Gwen Gaze), is an aristocratic British girl and Hoppy's (William Boyd) new employer. When Cassidy refuses to be ordered, Lorna has him arrested for horse stealing. The dumbfounded sheriff (Earle Hodgins) is even more puzzled when Miss Drake turns right around and demands that Hoppy be released into her custody.
Buck Randall (Buck Jones), a carefree cowboy whose popularity with the local saloon girls becomes the talk of the town. The new marshal, Joseph Slyde (Russell Simpson), gets on Buck's bad side by enforcing a "no gun" rule. Buck returns the favor by falling in love with the marshal's mistreated wife, Mary (Mary Doran), and she asks her husband for a divorce so she can marry Buck.
Windy (George "Gabby" Hayes) makes the mistake of accusing the buyer, Lazy-J owner Tom Hamilton (Frederick Burton), of the theft, but Lucky (Russell Hayden) suspects the foreman Dave Talbot (Stanley Ridges). Hamilton is murdered, however, and Talbot has the perfect alibi: He was playing cards at the Mirage Bar where Hoppy (William Boyd) had gotten himself a job under the guise of being the noted gambler Bill Thompson. With Talbot not able to be in two places at the same time, the marshal (Jack Rockwell) has no choice but to arrest Lucky for murder.