Under Southern Skies (1915)

Lelia Crofton, a Louisiana belle of the 1860s, loves Burleigh Mavor. By chance, she sees one of her father's black stablemen making love to a neighbor's maid, whom she supposed was white. The incident shocks Lelia and leaves a great impression upon her. When she rejects suitor Steve Daubeney, he threatens to expose a damaging secret about her mother, whom she has never met. Remembering the incident with the neighbor's maid, Lelia worries that her mother might be black, and when Daubeney learns of her fears, he leads her to believe that they are well-founded.