Upon the marriage of Lady Annabelle Croydon, Marie Wilder has moved to the Harvard's home to work as a housekeeper. When an ancient box is discovered belonging to Annabelle's mother, the late Lady Sandford, a mysterious locket is found amongst them. Intrigued by the letters inscribed upon it, Marie, with the help of her detective fiance, delves into it's history and uncovers a secret involving an ancient family in Sandford.