The Casebusters investigate accidents at an abandoned theater—where a ghost is the chief suspect! Ever since the new mall opened on the other side of Redoaks, the area around the historic Culbertson Theater has been abandoned. But when a local developer wants to bulldoze the area and turn it into a shopping center, someone inside the theater decides to take matters into his own hands—hands that may be alive or dead. After a sandbag falls on a building inspector’s shoulder—the latest in a string of suspicious accidents—kid detectives Brian and Sean Quinn decide to investigate. Sean’s friend Sam suspects it is the work of the ghost of Horatio Hamilton, an actor who died in the theater decades before, but Miss Beezly—the strange old woman who runs the theater—says that Horatio’s ghost is too polite for such misbehavior. Someone is pulling these dangerous pranks, and Brian and Sean better find out fast—in case the next sandbag falls on a detective!