She doesn't have a friend in the world, except her pet mouse, Pemberley, with whom she shares her dingy attic bedroom.Then, on the heels of a rather devastating announcement made by her mother and father, Tabitha receives a mysterious invitation to the country estate of the wealthy but reclusive Countess of Windermere, whose mansion is rumored to be haunted. There, she finds herself among five other children, none of them sure why they've been summoned. But soon, a very big secret will be revealed— a secret that will change their lives forever and put Tabitha’s investigative skills to the test.