We don't have a summary for Season 1 yet. Hang in there, or go ahead and contribute one.
Season Main Cast

Don Messick
voices Scooby-Doo
Lennie Weinrib
voices Scrappy-Doo
Casey Kasem
voices Shaggy Rogers
Heather North
voices Daphne Blake
Frank Welker
voices Fred Jones
Patricia Stevens
voices Velma Dinkley