The first incarnation of what has become a franchise-of-sorts, Scooby-Doo is a large, loveable but cowardly Great Dane who hangs around four California high school students (Fred, Velma, Daphne and Shaggy). The four teen-agers are in constant search of mysteries and adventures, driving around in a bright green van known as the Mystery Machine. Many of the group's adventures involve villians who take on supernatural disguises (ghosts and monsters); the villians' activities usually involve blackmail, theft, fraud and other forms of corruption.