Young Tony, unable to make a living in crowded and fast-paced London, goes to South America in search of his fortune. He soon becomes the owner of a saloon and dance hall. One of the dancers in his place, Maxine, falls in love with him, but Tony is still in love with his childhood sweetheart Una, although Una is now a "party girl" back in London and has forgotten about Tony. However, Tony comes into an unexpected inheritance, along with a title, and returns to London for Una. Although disappointed with Una's current lifestyle, he asks her to marry him despite her "indiscretions". However, the night before they are to be married Una confesses a deep, dark secret to Tony that could change their lives forever.

In 1898 friends John Thomas and Lars Larson travel to the Yukon with their wives to make their fortunes. While in Alaska Thomas' wife gives birth to a boy, and Larson's wife has a girl, Julia. However, Larson spots a birthmark on his daughter's shoulder that resembles one on Thomas' shoulder, and he begins to suspect that he may not actually be the girl's father. Over the next 20 years the two become millionaires, but Larson's wife dies. Julia and Thomas fall in love and wish to marry, but Larson is determined to oppose it.