No Choice But Seduction by Johanna Lindsey
When Sir Anthony Malory's daughter is abducted from Hyde Park, the ransom note mistakenly falls into the hands of Boyd Anderson, a hot-headed sea captain, who vows to find the missing girl.
Vivacious Katey Tyler, hoping to meet her relatives in England and seek adventure and romance on a grand tour of Europe, finds more than she bargains for when she discovers a little girl bound and gagged in a remote country inn. She escorts the girl back to her family in London, but finds that she is blamed for kidnapping the very girl she rescued! Little does Katey realize that with Captain Anderson she's about to experience more adventure and passion than she ever imagined, as well as learning the startling truth about her real father's identity.