12-Year Old Ben Tennyson is transported to Crystal Cove by accident, when he meets the Mystery Inc. gang. Shaggy and Scooby are chosen to watch over Ben, while Fred, Daphne and Velma handle the mystery.
- Scooby-Doo (Frank Welker)
- Shaggy Rogers (Matthew Lillard)
- Fred Chiles (Frank Welker)
- Daphne Blake (Grey DeLisle)
- Velma Dinkley (Mindy Cohn)
- Ben Tennyson (Tara Strong)
- Sheriff Bronson Stone (Patrick Warbutton)
- Mayor Janet Nettles (Kate Higgins)
- Gary and Ethan (Jeff Bennett and Mitch Watson)
- Hot Dog Water (Linda Cardellini)
- Prof. Leonidas Grant (David Warner) - Reason: because he has Plumber Technology
- Kirk Lloyd (Rene Auberjoinis) - Reason: for wandering the scene of the crime
- Phobe Henrikson (Minnie Driver) - Reason: for enforcing the Alien Registration act!
- Gloria Vance (CCH Pounder) - Reason: for holding Private Property!
- Gary and Ethan: because to release to Golden Calf Creature!
- Sheriff Bronson Stone: to free the Morloks