Leonora, the daughter of a poor Italian lacemaker, is unable to afford voice lessons until wealthy Americans Mr. and Mrs. Stuart adopt her and her younger sister Nina. Leonora soon wins fame as the Parisian prima donna "La Vecci," whose beauty attracts many admirers, including Phillip Gardiner and his Spanish cousin, Count Nerval. Worried by his excessive jealousy but very much in love, Leonora marries the count and travels with him to the United States. Still infatuated with her, Phillip invites Leonora to visit his family in New Orleans, and when she rebuffs him, he turns his attention to Nina. Learning that Nina's sweetheart, Dr. Paul Spencer, will join them, Leonora begs Phillip to leave the girl in peace, but he only seizes the prima donna in his arms and kisses her. Leonora faints during an attempt to stab Phillip, but on awakening, she finds him dead and herself accused of murder. Leonora's name is cleared when Phillip's Creole lover confesses that it was she who stabbed him, after which Leonora and the count renew their love.