A Broken Vessel (Julian Kestrel Mysteries, #2)

Julian Kestrel, the dandy detective of Regency London, is most decidedly a man of the world and, through his valet, Dipper, reformed Cockney pickpocket, is not without ties to the underworld. One such connection is Dipper's sister Sally, a prostitute who accidentally happens across the possibility of murder while picking her clients' pockets. Since Sally is not quite in the position to go to the police with her knowledge, she and Julian must chase the clues all through London, from glittery parlors to the dank halls of a home for fallen women.