June 1814, and the royal families of Austria, Russia, and the German states have gathered in London at the Prince Regent's invitation to celebrate the defeat of Napoleon and the restoration of monarchical control throughout Europe. But the festive atmosphere is marred one warm summer evening by the brutal murder of a disgraced British nobleman long thought dead. Few in London were surprised when they heard the ne'er-do-well had died in New South Wales in 1799. But those reports were obviously wrong. Sebastian St. Cyr, Viscount Devlin, is drawn into the investigation by his valet, Jules Calhoun.