Ellie is determined to get to the bottom of the mystery that has eluded Lethersby scholars for more than 100 hundred years by figuring out what happened to their long-lost queen, a young royal who disappeared shortly after the outbreak of the First World War. With the help of Mark, a handsome castle staff member who shares her love of history, she might be able to unravel the queen's story. But Mark is keeping his own secret from her, and what they discover together could change everything for Ellie-and the entire kingdom.