His Bonnie Bride (Highland Brides 1) by Hannah Howell

All along the border, battle was a way of life as both Englishmen and Scots rode off across the moors to do as their fathers had done and their fathers before them.

So when Storm Eldon was kidnapped by her family's ancestral enemies, she knew there were rules to be honored by both sides. If her stepmother agreed to the ransom, Storm would not be harmed by the handsome Highland warrior who held her captive. But as days of waiting turned into weeks, it began to be clear that in this contest of wills, no one was fighting fair.