Before his death, Florida businessman de Costa asks his daughter Isobel to search for her half sister Anita in South America so that his estate may be shared between them. Isobel, a kindly and refined young woman, arrives in Buenos Aires just after Anita, who resembles her sister in appearance but not in disposition, has attempted to poison her lover, Umberto. While Isobel languishes in prison, having been arrested for the crime, Anita and her new paramour, Don Pedro, establish themselves in the de Costa household in Florida. Posing as her sister, Anita decides to marry Isobel's fiancé, Robert Grant, which so enrages Pedro that he cables the authorities in Buenos Aires that they have imprisoned the wrong woman. Isobel arrives home immediately following the ceremony, but Umberto appears and reveals that he had married Anita five years previously. Having survived her sister's treachery, Isobel settles down with Robert.
