The Mega Mondo Pop Cartoon-a-Con in sunny California marks the spot for mystery in this all-new original Scooby-Doo adventure! The Mystery Inc. pals -- Fred, Daphne, Velma, Shaggy and Scooby -- head to the annual convention, but they're not there … Frank Welker, Mindy Cohn, Grey DeLisle, Matthew Lillard, Diedrich Bader, Dee Bradley Baker, Jeff Bennett Added on HBO 2023-06-27, leaving 2024-10-01. Youtube Trailer