Following the atmospheric and award-winning gothic historical mystery debut, The Curse of Penryth Hall, USA Today bestselling author Jess Armstrong's heroine, Ruby Vaughn, returns in The Secret of the Three Fates, where the Scottish Hills hold ghosts of the past that threaten Ruby's present.

American heiress Ruby Vaughn still hasn't entirely forgiven her octogenarian employer and housemate Mr. Owen for bringing the occult into their lives during her recent trip to Cornwall. He claims their journey to Manhurst Castle in the Scottish Borders is simply to appraise and acquire illuminated manuscripts for their rare books shop, however when Ruby discovers there are no manuscripts and receives news of a séance to be held that very night, she begins to grow suspicious about the true reason why they have come.

The Great War left grieving families willing to sacrifice anything for the chance to say goodbye to a lost loved one. Mr. Owen is no exception. He is desperate to speak to his son, but he doesn't want to face the spirits alone. When the séance—hosted by a trio of mediums billing themselves as The Three Fates—goes awry, Mr. Owen's secrets begin to unravel, threatening to reveal a history that he has been running from for half his life. Something Ruby knows all too well how to do.

When Ruby finds one of the Three Fates murdered the night of the seance, she and Mr. Owen quickly become the prime suspects. To clear their names, Ruby enlists the help of Ruan Kivell, the folk healer Pellar who helped her weeks before in Cornwall. As their investigation progresses Ruby and Ruan realize someone is determined to prevent them from uncovering the truth about what happened to the dead medium.