One dead actress, one dead maid - and implications that Sebastian St. Cyr - the Viscount of Hendon was the murderer. Sebastian takes to ground in order to clear his name. He rents a room in a section of London where the aristocracy do not live - is befriended by a young pickpocket who becomes his “guide” to this part of society mostly unknown to St. Cyr - and together they set out to investigate the events that lead to the murder of Rachel York. Sebastian has three or four encounters with the police where he is able to elude capture and eventual imprisonment. Sebastian and Tom uncover the pieces of the puzzle - implicating some men close to the Prince of Wales as selling Great Britain’s secrets to France. A puzzle that I did not find very intriguing - although the final scene with Kat, Lord Wilcox and the warehouse made for a great action scene. 
While I will probably read another of the St. Cyr series - this first installment did NOT thrill me. Partly because I could not help but draw parallels in my mind to Sir Thomas Lynley - and unless Tom is a continuing character - St. Cyr does not have a Barbara Havers.