Eugenie and the Earl — Marina Oliver

Saved from a Parisian mob, Eugenie is puzzled by her rescuer. Her parents died in Switzerland, and in order to return to England she is forced in 1812 to work in taverns and walk through France, at war with England. When threatened by a Parisian mob a stranger rescues her, and offers to help her reach the coast. Hugues not only does this, he finds her a boat to take her to England and gives her money for the onward journey to her uncle's house in Hampshire. Her Uncle, the Duke of Norwich, and his second wife welcome her, and Uncle Jerome takes her to see her family home, where they discover the bailiff has been robbing her instead of sending money to Switzerland. Leaving his own people to put matters right, he and Arabella takes her to London for the Little Season.
The Duke is concerned by his son George's behaviour. He is a spendthrift and tried to persuade a young heiress to elope with him. He has also broken into the Duke's desk and stolen money. Eugenie is puzzled by George who spends time in the old half-ruined castle beside the modern house. It is later discovered George has copied Government papers and sold them to the French. In London Eugenie meets the Earl of Lyndhurst, who is her rescuer Hugues, an agent working in France. The Duke forces George to return to Hampshire, with two men to guard him, but he eludes them and hides in London. The Earl returns to France to try and undo the harm George has done. Invited to a wedding, Eugenie and the Earl become betrothed.