Although the entire internet agrees that this was a 1938 film, the copy I watched from Amazon had a 1942 copyright notice. Twelve-year-old actress Shirley Mills does a nude scene, and there are a few ripped bodice moments for a couple of the adult actresses. Those hillbillies in the Ozarks were marrying their women too young.
The Scarlet Pimpernel is the original hero with a secret identity, I guess. He is a seemingly foppish English aristocrat who dons disguises and leaves taunting poems as the Scarlet Pimpernel, rescuing Frenchmen who are headed toward beheading during Robespierre's Reign of Terror. This movie is "the return" because there had previously been another successful Pimpernel movie starring Leslie Howard and Merle Oberon. James Mason plays a secondary character.