trying to find a book

[silentwife]

i am trying to find a book that i read years ago. I cann't remember the title or the author, just alittle about the story line. I think it was either set in Scotland or England, about a lady and her brother who were kidnaped while on a horse back ride. She was discuised as a young boy and later found out to be a girl, her brother was to be ransomed back to their father but he refused to pay for her aswell right away. She fell in love with her captor then was again kidnaped by a man who was obsesed by her and he also killed her mother, i know it is not much to go on considering the large amount of historical romance novels over the years but this one just keeps sticking out in my mind and i would greatly love to locate it!