The Valcourt Heiress — Catherine Coulter

When Garron of Kersey returns home from the king's service to claim his title as Baron Wareham, he's shocked to find Wareham Castle very nearly destroyed by a man called the Black Demon.

According to the last starving servants still clinging to life inside the castle walls, the Black Demon was looking for gold belonging to Garron's brother Arthur. Among his remaining servants is the enigmatic Merry, the bastard child of the castle's priest. Garron quickly realizes that she is much more than a servant: She reads and writes and makes lists, just as he does. Together they bring Wareham back to its former splendor.

But this is only the beginning. Did Arthur have a cache of gold? Who is the Black Demon? And the biggest question of all: Who is Merry?