What is the main conflict in The Favored Child by Philippa Gregory?

ulia Lacey and Richard McAdams are raised as cousins by Julia's mother, Celia. Richard's father, John, is away attempting to make enough money to sustain their household and to rebuild Wildeacre, the family estate. As the plot unfolds, Julia and Richard will learn that they are brother and sister, born of Beatrice Lacey McAdams and her brother, Harry. As they grow up together under the care of Celia, Julia and Richard know nothing of the family secrets other than the fact that it was Beatrice's greed that prompted the villagers to burn her house and kill her, and that the night of violence caused the death of Harry Lacey, squire of Wildacre.