What does Sophie discover about herself in the closing chapters of the book?

All of her life, Sophie thinks her family had died in a car accident, when, in fact, her grandmother and brother are alive. Sophie reunites with them, as a result of solving the last riddle in the keystone. Sophie is finally at peace and all of her questions regarding her family are revealed. She was fiercely protected by her grandparents because she is a direct descendant of Jesus Christ and Mary Magdalene.