Marcia Calhoun, a talented but penniless singer, leaves her Southern home hoping to study opera in New York. Her instructor, Professor Didot, promises her a contract on the condition that she receive formal training in Italy for one year. Didot introduces Marcia to millionaire Philip Bradley, who offers to pay for her studies if she will accompany him to Italy as his mistress. Desperate for money, she agrees, but several months later, Philip abandons her. Marcia continues her studies, and on the night of her highly successful debut in Paris, Robert Carroll, with whom she has fallen deeply in love, proposes. When Marcia confesses her past, however, he deserts her, whereupon she vows to ruin Philip and his family. Because Philip has died, she seeks her revenge through his brother John, who comes to love her so dearly that he reveals all of his business secrets to her. Through dealings with his rivals, Marcia ruins John, but he proposes nonetheless, promising to right his brother's wrong.