"The Cambist and Lord Iron" by Daniel Abraham
follows two men: Edmund Scarasso, Lord Iron, famous as one of the most extraordinarily debauched, corrupt, and wicked nobles in the city, and Olaf Neddelsohn, a cambist (exchanger of currencies) at the Magdalen Gate postal authority, not famous at all, whose greatest vice is the reading of adventure novels. The fates of these two grow entwined as Lord Iron sets for the cambist three challenges of exchange, each with greater consequences than the last.
The story is publicly available under a Creative Commons license — in text here
, and as a podcast here