The first full-length animated Scooby-Doo adventure for the big screen is the never-before told stories of Scooby-Doo₂s origins and the greatest mystery in the career of Mystery Inc. The story reveals how lifelong friends Scooby and Shaggy first met and how they joined with young detectives Fred, Velma and Daphne to form the famous Mystery Inc. Now, with hundreds of cases solved and adventures shared, Scooby and the gang face their biggest, most challenging mystery ever.

With hundreds of cases solved and adventures shared, Scooby and the gang face their biggest, most challenging mystery ever. Discovering that Scooby has a secret legacy and epic destiny, Shaggy remembers how he met the puppy and how Mystery, Inc. was formed.