Wavesbury

It's wonderful to be a wealthy French marquise living in luxury. But it becomes far less pleasant during the French Revolution, especially with Robespierre's reign of terror in full swing. Young William Wavesbury, along with his brother-in-law Paul – and twin sister Margaret, who refuses to be left behind – must embark on a dangerous mission to Paris to save Paul's sister from a sentence that, in those times, could only mean one thing. Death by guillotine.
Even back home in England, it isn't safe. The old Earl, David Wavesbury, is still a valuable military advisor, making him a target for French spies – particularly one with personal reasons for revenge against his family. What began as a harmless encounter with a gallant highwayman ends in a fight for life almost on the doorstep of the Wavesbury home.
Paul finds himself on a mysterious list of people who are being murdered one by one, seemingly without reason. The trail leads in a clear direction, leaving him no choice but to venture back into hostile Paris with William Wavesbury. A traitor in their own ranks then forces their ladies to undertake the perilous journey as well. The disfigured overseer of Paris's brothels certainly isn't going to let such prey escape.
Maximilien Robespierre, the uncrowned ruler of the new French Republic, is at the height of his power. He has no idea, however, that across the English Channel, a group of people are plotting a conspiracy to end his rule once and for all.

The book includes an extensive family tree of the Wavesbury family.