In the Highlander's Bed by Cathy Maxwell

Highland warrior Gordon Lachlan has spent his life fiercely battling the English. Now, to claim victory for his clan, he must retrieve the legendary Sword of the MacKenna from the hands of his mortal enemies. His plan: to kidnap Constance Cameron from her remote boarding school and force her wellborn relatives to surrender the sword as her ransom.

But Lachlan is surprised that the woman he's snatched from her bed is no malleable miss. Constance longs for adventure. She's tantalized by Lachlan and his passionate cause . . . and tempted enough by his seductive ways to wonder what it would be like to find herself in the Highlander's bed . . .