Someone has been passing counterfeit cash at the big top, and so our heroes, the Three Mesquiteers (legendary cowboy actors Ray "Crash" Corrigan, Robert Livingston and Max Terhune), join the circus to help find the culprit. Their pal Harris emerges as the lead suspect, but the boys set their sights on Harris's shady partner, Rigby. And as if things weren't complicated enough, Harris's beautiful daughter Nancy (Anne Bennett) enters the picture.