Scooby-Doo and the gang, along with the rock group Josie and the Pussycats, battle ghosts haunting the Dixie Queen Showboat on the Missouri River--or is it the "eerie" canal? The mystery begins when the 100-year-old ghost of Mark Twain's "Tom Sawyer" character, Injun Joe, along with another bad ghost, drag chains, move objects and make scary noises.