When young Lotus Flower sees an unconscious man floating in the water near the seashore, she quickly gets help for him. The man is Allen Carver, an American visiting China. Soon the two have fallen in love, and Carver promises to take her with him when he returns home. But Carver's friends discourage him from doing this, and he returns to the USA alone. By the time the two of them meet again, much has changed, and their reunion proves very trying for them both.

A spoiled young rich girl is forced by misfortune to fight for survival in the slums and alleys, where she becomes involved with all manner of unpleasantness.

Dr. Lorenz, a mad scientist, wants to keep his elderly wife young. He does this by kidnapping young females and extracting fluid from them. He then injects this fluid into his wife. What a diabolical guy!

Blizzard, deranged from a childhood operation in which both his legs were perhaps needlessly amputated after an accident, becomes a vicious criminal, and eventually mob leader of the San Francisco underworld. Out for revenge against the surgeon who performed his operation, he undergoes brain surgery which has a chance of altering his anti-social behavior.

Mary Blake arrives at Blackie Norton's Paradise gambling hall and beer garden looking for work as a singer. Blackie embarrasses her by asking to see her legs, but does hire 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 which she sorrowfully stands by. Later, when he makes up posters featuring Mary in tights, she does leave for the Tivoli. Blackie gets an injunction against Burley, but knocks out the process server when he hears Mary's performance as Marguerite in "Faust". She asks her to marry him and she agrees to go back to the Paradise as his kind of singer, but Blackie's childhood chum Father Tim intervenes. After Blackie slugs the priest, Mary leaves. She is soon the star of the Tivoli and Blackie's place is closed down...