In November 1817, anonymous satirist Juliet MacKenzie is found murdered in a Covent Garden brothel. Her caricatures attacked influential figures in society and government, giving Sebastian a long list of suspects among people close to the Prince Regent and those damaged by her private secrets.
A royal ring connects Juliet to rumours that the Honours of Scotland were secretly taken to London after the 1707 union. As further murders follow and Hero is targeted, Sebastian investigates whether the missing crown jewels, Lord Jarvis's political knowledge and the satirist's concealed identity are parts of the same conspiracy.