Lord Tony's Wife by Baroness Emma Orczy (1865 - 1947)

after some disturbing happenings including an angry mob and an assault on Yvonne by her own father. Later a man set on revenge and with the help of Chauvelin steal Yvonne away, and Lord Tony must go to the Scarlet Pimpernel for assistance. Will they be able to save her and her father from the clutches of Pierre Adet and Chauvelin? Will Lord Tony ever even see his wife again? (Summary by fiddlesticks)

Series:
1: The Scarlet Pimpernel
2: I Will Repay
2.5: The League of the Scarlet Pimpernel
3: The Elusive Pimpernel
4: El Dorado: Further Adventures of the Scarlet Pimpernel
5: Lord Tony's Wife
6: The Triumph of the Scarlet Pimpernel
7: Sir Percy Hits Back
Prequel: The Laughing Cavalier