In Shanghai, China, destitute Brooklyn chorus girl Dixie Pomeroy is picked up on the street by Doctor Omar, a mystic and opportunist, as she is being taken to jail for vagrancy.  Omar and his friend make a deal with the police and bring Dixie to "Mother" Gin Sling's casino, where they expect Mother Gin Sling to provide her with work.

That night, Victoria Charteris, a sophisticated British boarding school graduate, comes with an escort to the casino, which draws an international collection of gamblers and other desperate characters, and is intoxicated by the atmosphere of the place.  When Victoria spots the handsome Omar, she demands an introduction, and Omar allows himself to be seduced by the beautiful young woman, who calls herself "Poppy Smith."  Mother Gin Sling, meanwhile, learns that a wealthy Briton has bought her property and that she will be forced to close her casino by the Chinese New Year.  Mother Gin Sling plots revenge against the man, whom she believes is ruthlessly driving her out of business, and learns from Dixie that he is Sir Guy Charteris, Victoria's father, and Mother Gin Sling's husband from her youth.

Over a period of several weeks, Victoria degenerates into a drunken, desperate gambler and loses thousands of pounds and property while clinging to an indifferent Omar.  When someone sells Poppy's valuable necklace back to Charteris, he realizes that his daughter is in dire straits and insists that she return to England.

He later accepts an invitation to a Chinese New Year dinner from Mother Gin Sling, whose identity is unknown to him.  At the dinner he soon learns that Mother Gin Sling has brought together some of her arch enemies, including himself.  Charteris is highly suspicious until Mother Gin Sling calls him by the pseudonym he used in China when he was a young man, and finally recognizes her as his former wife.

Mother Gin Sling now accuses Charteris of having robbed her of her money and child, abandoned her and sold her into labor.  Charteris denies any wrongdoing and maintains that although he did divorce her, he deposited her money in her name in a still-active bank account.  He further claims to have rescued the infant Victoria from a hospital where she had been abandoned.

Victoria, who never boarded the plane to England and has no idea she is of mixed heritage, now appears at the dinner party and, completely rebellious, refuses to leave the casino at Charteris' command.  Mother Gin Sling, realizing that Victoria is her daughter, asks to quell Victoria's outburst on her own, but when Victoria insults her, Mother Gin Sling denounces her daughter and shoots her.  Charteris, who has been waiting outside the door, hears the report, which mixes in with the sound of firecrackers from the passing Chinese New Year Parade.