Sam, Derek and Caitlin have encountered many mysteries together, but when they visit Maymont, Richmond's historic estate, danger is lurking at every turn. A chance meeting with a mysterious stranger leads to a frantic chase and a desperate message to save Maymont's bald eagles. When Sam receives an eerie warning in the middle of the night, Derek and Caitlin devise a plan that leads them high into the Blue Ridge Mountains. To save the eagles, the kids must find a secret abandoned palace, survive the wilds of the Appalachian Trail and avoid capture by criminals, all before midnight.