The Case of the School Ghost (The Buddy Files)

Its the night of the Fourth Grade sleepover and Buddy is invited. When he gets to school Mr. Poe the custodian tells everyone about the ghost that haunts the school grounds. There are no such things as ghosts right? But secret notes unusual banging and a ghostly voice may indicate otherwise. Could this be why Connor and Michael are acting so strange? Is there really a ghost in the school? Buddy is determined to find out!