In the summer of 1876, San Francisco is in the fierce grip of a record-breaking heat wave and a smallpox epidemic. Through the window of a railroad saloon, a young woman named Jenny Bonnet is shot dead. The survivor, her friend Blanche Beunon, is a French burlesque dancer. Over the next three days, she will risk everything to bring Jenny's murderer to justice --- if he doesn't track her down first.