In 15th century England, 14-year-old Celeste is arranged to marry her 38-year-old widower uncle Lord Archibald Barret by her father Lord Henry Clement after her aunt passes away during childbirth. Fearing marriage and death by childbirth, Celeste escapes into the night and seeks refuge at the Romsey Abbey. Mother Ignatius takes Celeste under her wing and mentors her into becoming a nun at the abbey. There she meets Sister Mary Frances, her comfort and kindred spirit.