Sequel to the hugely successful 2002 live-action version of the classic children's cartoon series. Everything is going well for the Mystery Inc. gang: they're enjoying a high profile, and the public adore them so much their hometown of Coolsville has even opened a special museum in their honour. But things take a turn for the worse when a masked villain tries to take control of the city using a Monster Machine that brings to life the gang's past enemies -
including the 10,000 Volt Ghost, Captain Cutler and The Creeper - reproductions of whom are on display in the museum. To make matters worse, a local TV reporter (Alicia Silverstone) has got it in for Mystery Inc., airing a series of reports that call their bravery and intelligence into question. Can Scooby, Shaggy and the gang regain their credibility and vanquish the dastardly Monster Machine operator?