The Ghost Of Fossil Glen (Ghost Mysteries)

Sixth-grader Allie Nichols knows she's being pursued by a ghost. Her friend Karen calls Allie a liar and doesn't want to hear "stuff like that." But her old pal, Dub, listens eagerly as Allie tells him about a girl who begs "Help me," and a terrible nightmare in which that girl falls to her death. Who is the ghost girl? And what does she want from Allie?