Louis La Farge journeys to a little Alsatian village and there makes love to a pretty shepherdess named Marie Beaupre. Following his departure, Marie is cast out of the village, and, forced to survive in the mountains alone, she goes mad. On a hunting trip, hypnotist Dr. Cochefort and his friend Delaunay meet the "witch woman," as she is called, and take her to Paris, where she is cured and then named the heir to Delaunay's fortune. Her adopted guardian introduces her to Louis's twin brother Maurice, and she, believing him to be Louis, flirts with him while searching for an opportunity to obtain revenge. Andrea Montignac, Louis's mistress, begs Marie to give him up, not realizing that it is Maurice who courts her, and, at a masked ball, Marie announces that Louis and Andrea are engaged. Louis only laughs and seizes Marie, whereupon Andrea shoots him. When Maurice enters, both women realize their mistake, and Andrea commits suicide. Maurice then gives Marie his forgiveness and his love.