The Girl in the Locked Room: A Ghost Story by Mary Downing Hahn
A family moves into an old abandoned house. Jules’s parents love the house, but Jules is frightened and feels a sense of foreboding. When she sees a pale face in an upstairs window, though, she can’t stop wondering about the eerie presence on the top floor—in a room with a locked door. Could it be someone who lived in the house a century earlier? Her fear replaced by fascination, Jules is determined to make contact with the mysterious figure and help unlock the door. Past and present intersect as she and her ghostly friend discover—and change—the fate of the family who lived in the house all those many years ago.