Red Skelton plays Aubrey Filmore, a feather-brained but lovable bellboy who dreams of becoming an agent for the Union's secret service during the Civil War. He gets his chance when he inadvertently causes the capture of a notorious Confederate spy known as "The Grey Spider" and adopts the spy's identity. The plot thickens when Aubrey meets the beautiful Confederate agent Sallyann Weatharby (Arlene Dahl) and falls in love with her. He is then forced to carry on the masquerade by posing as The Grey Spider and conveying false maps and instructions to deceive the Confederate forces when they plan their strategy at an upcoming battle.
Comic genius Buster Keaton was instrumental in creating numerous memorable gags in this endearing film and veteran director Edward Sedgwick came out of retirement to make the picture. For fans of classic comedy, A Southern Yankee is truly a piece of motion picture history.