Mystery Inc. are called by Alan Dinsdale, a librarian and old friend of Velma to Hambridge Library. He explains that ghosts have started appearing and that visitors have fled. The only person left is Walter Peabody, Alan's assistant. He believes that someone has used the Tome of Doom, a magical book that releases supernatural creatures. It just so happens that Shaggy and Scooby come across the Tome of Doom and start using it to trap several monsters back inside its pages. Now Fred, Velma, Daphne, Shaggy and Scooby are on a wild goose chase, trying to solve the mystery and sealing the monsters back in the book.