The story begins as the intrepid Mystery Inc. gang is being honored at the Coolsonian Criminology Museum, where costumes of the creepy critters they've caught over the years are on exhibit. Then, suddenly, as they're walking the red carpet, the Pterodactyl Ghost comes back to life, along with the Black Knight Ghost, the Skelemen, Tar Monster, Captain Cutler's Ghost, Cotton Candy Glob and Miner 49er. It seems that someone has invented a dastardly monster-making machine, and the local heroes are blamed for the mayhem by an aggressive investigative reporter (Alicia Silverstone) who tries to rally the citizens of Coolsville against Mystery Inc..

As Fred (Freddie Prinze Jr.) and Daphne (Sarah Michelle Gellar) assemble clues to unmask the villain - perhaps jailbird Jeremiah "Old Man" Wickles (Peter Boyle) - intelligent-but-insecure Velma (Linda Cardellini) becomes infatuated with a key suspect, Museum curator Patrick Wisely (Seth Green), who seems to be working both sides of the psycho street. Meanwhile, Norville "Shaggy" Rogers (Matthew Lillard) and his CG canine pal Scooby-Doo are forced to confront their fears and feelings of inadequacy. And for kids, there are life lessons to be learned about self-esteem, acceptance and teamwork within these subplots. On the Granger Movie Gauge of 1 to 10, "Scooby-Doo 2: Monsters Unleashed" is a screwball 6. It's family-friendly fun.