In San Francisco, in the year 1906, Mary Blake (Jeanette MacDonald), a classical trained singer from Colorado arrives at Blackie Norton's (Clark Gable) Paradise gambling hall in Barbary Coast. Mary who is out of work, is trying her luck to look for a job. Although, Mary has no professional experience whatsoever in the singing industry, Blackie decides to offer her a two year contract. Meanwhile, Jack Burley (Jack Holt) owns a Tivoli Opera House and instantly becomes attracted by Mary's voice. He then decides to offer the beautiful singer an audition whose dreams just happens to be an opera singer. A series of events take turns between the two rivals in order to capture Mary's love and attention. When a ground quakes on the night, Mary sings a rendition song called San Francisco, Blackie tries to search for Mary and when he finally gets to meet Mary again, he kneels down to thank God for reuniting them once again.