For as long as she could remember, Ab and her family had spent summers on Penobscot Island, off the coast of Maine – and far away from the sun-baked streets of their home in New York City. And every year, she spent time with Bean Carver who was her best friend, even if he didn’t seem to notice she was a girl. This year, Bean tells Ab that the Moses Webster House where she is staying with her parents is haunted, and the two friends become immersed in the history of the house and solving a mystery involving missing treasure, stolen paintings, a wailing apparition, and a tragic shipwreck. The discovery of certain ancient devices hidden in the walls and floors of the old house lead them deeper and deeper through a web of secrets and peril, closer and closer to the chilling truth of the missing grave.