In this western, the Three Mesquiteers must find a killer and his band after they murder an official from the State Agricultural Service who had come to investigate an outbreak of hoof and mouth disease. The killer is fearful that the official would quarantine his entire herd. Unfortunately for the foolish rancher, if the herd is not isolated, all of his cows and those of his neighbors will die anyway. The heroes are assisted by Buck the clever Great Dane.
Ray Corrigan
as Tucson Smith
Max Terhune
as Lullaby Joslin
Ralph Byrd
as Larry Smith
Sandra Corday
as Ann Evans
Robert Warwick
as John Evans
Cornelius Keefe
as Tom Brent
Sammy McKim
as Mickey Evans
Hal Taliaferro
as Henchman Luke
Willie Fung
as Ranch Cook
Buck
as Buck
