The Mystery of a Hansom Cab takes place in Melbourne, Australia and involves an investigation into a homicide, after a corpse is discovered in the evening, in a hansom cab. The city of Melbourne plays a significant role in the plot and, as the author describes: "Over all the great city hung a cloud of smoke like a pall." The killer's identity is not as significant a revelation in the story as are the roles of the influential and secretive Frettlby family, and their secret: they have an illegitimate daughter living on the streets. The class divide between Melbourne's wealthy and less fortunate is addressed throughout the plot.