At the start of the Civil War, Sam Davis leaves his plantation family to enlist in the Confederate Army. Two years later, returning to battle after a brief furlough, Sam meets Polly Dover in Pulaski, Tennessee and falls in love. Posing as a Union herb doctor, Captain H. B. Shaw infiltrates the Union camp and passes military secrets to his Confederate peers. Betty English, another spy, tricks a Union captain into drawing a diagram of an upcoming maneuver, then with the help of her black slave, delivers the paper to Shaw, who entrusts Sam to take it to the front. After kissing Polly goodbye, Sam rides off with the document, followed closely by Union soldiers. Sam gives them a good chase but is finally caught. Despite numerous questionings and a trial, Sam refuses to reveal the identity of his fellow spies and is sentenced to hang. Surrounded by crying, admiring onlookers, Sam dies, a hero.
—The AFI catalog