December 1767. Alistair Douglas has been using the Decipherers, a secret network of contacts in London, to attempt to find two men implicated in a series of political murders in the mutinous American colonies. Rumours fly as anonymously printed attacks on the King and his ministers flow through the city. But, frustratingly, there are few leads.

Douglas is therefore pleased when he is assigned to a new duty. He must travel to Paris and ensure the outlawed radical writer and politician John Wilkes returns to England - the stipulation being that Wilkes must return of his own volition. It is soon clear there is a serious conspiracy afoot - and John Wilkes is first on the list of suspects.

But the Decipherers have reason to believe there is a highly placed intimate of the present government also involved . . .