Mary Blake arrives at Blackie Norton's Paradise gambling hall and beer garden looking for work as a singer. He embarrasses her by asking to see her legs, but he hires her. She faints from hunger. Nob Hill Socialite Jack Burley and Maestro Baldini of the Tivoli Opera House see her singing and offer her a chance to do opera, but Blackie has her under a two-year contract and she ruefully stands by it. Later, when he makes up posters featuring her in tights, she does leave for the Tivoli. He gets an injunction against Burley but knocks out the process server when he hears Mary perform as Marguerite in "Faust". She proposes marriage to him, and she agrees to go back to the Paradise as his kind of singer, but his childhood chum, Father Tim Mullin, intervenes. After he slugs him, Mary leaves. She is soon the star of the Tivoli and the Paradise is closed down. She sings a rousing "San Francisco" on behalf of the Paradise at the annual "Chicken Ball" and wins the $10,000 prize which Blackie throws to the floor. As she storms out of the hall, a terrible rumble betokens the famous 1906 San Francisco earthquake. Buildings collapse, streets split wide open, the city burns, and the army dynamites whole sections of town. After staggering around in a stupor, Blackie finds Father Mullin and they find Mary at a Salvation Army camp. Backed by hundreds of others, they look out over the ruins which are gradually replaced by the shining new city with a reprise of the title song.—Ed Stephan