It's October 1814. The war with France is finally over, Europe's diplomats are convening in Vienna for a conference that will put their world back together, and London finds itself in the grip of a series of terrifying murders eerily similar to the shocking Ratcliffe Highway murders of three years before. In 1811, two entire families were brutally murdered in their homes. A suspect - a young Irish seaman named John Murphy - was arrested. But before he could be brought to trial, Murphy hanged himself in his cell. The murders ceased, and London slowly began to breathe easier. But when the lead investigator, Sir Edwin Pym, is killed in the same brutal way, suddenly everyone is talking about the heinous crimes again, and the city is paralysed with terror.