Her Scottish Captor (Highland Mist 1) by Kate Wingo

Iain MacKinnon hates all things English. The laird of his clan, tragedy has turned Iain into a ruthless warrior who is determined to avenge the brutal murder of his twin brother at the hands of a villainous English earl.

To collect on the blood debt, Iain kidnaps the daughter of his sworn enemy and holds her for ransom.
Lady Yvette Beauchamp has heard many a fearful tale about the wild, barbaric men who inhabit the Scottish Highlands. Abducted on the eve of her wedding to an aging earl, Yvette has reason to fear the brooding chieftain who holds her against her will in his island castle. While the darkly handsome laird may desire her body, she’s certain that he covets the rich ransom even more, Yvette’s worth set at a staggering two thousand pounds.
When Yvette is forced to become the châtelaine of Iain’s castle, her duties constantly throw her into the laird’s path . . . and a very dangerous intrigue when she discovers that Iain’s mysterious guest is none other than Robert the Bruce, the newly crowned king of Scotland. With the Bruce in hiding at Castle Maoil – a bounty having been placed on his head by the English king – Yvette is now privy to one of Scotland’s best kept secrets. A secret she can either use to secure her freedom . . . or safeguard the Highland laird she has come to love.