From Western bounty hunters to superheroes, everyone needs help from Mystery Inc.! Scooby-Doo, Shaggy, Velma, Daphne and Fred pack up the Mystery Machine and head to the hippie city of Karma Corners...and everything seems groovy until a group of ghostly parents forces the party to end! Can the team--assisted by Green Lantern and Green Arrow--find out what these guilt-causing ghosts truly want from the town? Then, Scooby and his friends learn more than just karate moves from Hong Kong Phooey when fire-breathing kung fu dragons take over a town. But the Mystery Inc. crew's not done tackling cases just yet. When a fortune-teller makes Plastic Man's sidekick Woozy Winks doubt his own fate, the gang investigates the wacky psychic's claims! They meet Jonah Hex and the monster of the Old West, and run into Top Cat and his group of famous felines to find out just why Hoagy's Alley is haunted. These meddling kids then clash with the Challengers of the Unknown, who think they can't solve a real supernatural mystery! Will the teen sleuths prove the Challengers wrong and deliver the Mystic Elixir serum to the Gnome King?