In early-1900s Los Angeles— an era of courting, ragtime, suffragettes, and widespread corruption— a socialite turned police matron tracks down the murderer of a white woman in Chinatown, while trying to prevent the outbreak of a bloody tong war.
Los Angeles, 1908. In Chinatown, the most dangerous beat in Los Angeles, police matron Anna Blanc and her former sweetheart, Detective Joe Singer, discover the body of a white missionary woman, stuffed in a trunk in the apartment of her Chinese lover. If news about the murder gets out, there will be a violent backlash against the Chinese. Joe and Anna work to solve the crime quietly and keep the death a secret, reluctantly helped by the good-looking Mr. Jones, a prominent local leader.

Meanwhile, the kidnapping of two slave girls fuels existing tensions, leaving Chinatown poised on the verge of a bloody tong war. Joe orders Anna to stay away, but Anna is determined to solve the crime before news of the murder is leaked and Chinatown explodes.