In 1898, partners John Thomas and Lars Larson travel to the Yukon with their wives. In Alaska, a boy is born to Thomas and a girl to Larson. The latter discovers on his daughter's shoulder a birthmark resembling one on the shoulder of Thomas, creating a suspicion for which he plans future revenge. In the course of twenty years, Larson's wife dies, and the partners become millionaires. Larson is being cheated by his confidential man, James Curdy, who is threatened with exposure by James Bradley. Meanwhile, Julia Larson and Paul Thomas wish to wed, but the match is opposed by Larson. When Bradley is killed aboard Larson's yacht, Curdy persuades Larson that he is responsible, and Larson flees to the North. Paul is accused of the murder and sentenced to be hanged, but Larson returns to San Francisco after reading a notice about the trial. Rita, a halfbreed servant, confesses to exchanging the Larson-Thomas babies at birth, as the former wanted a girl and Thomas a boy. Curdy is convicted, and Paul is free to marry Julia.