A group of teenage friends and a Great Dane travel from town to town in their Mystery Inc. van. The gang stumble upon mysteries and investigate reports of ghosts, monsters, and other strange events. The group of amateur detectives are Freddy Jones (Frank Welker), the group’s handsome and inventive leader; Daphne Blake (Stefanianna Christopherson, later Heather North), Fred’s intuitive and wealthy girlfriend; Velma Dinkley (Nicole Jaffe), the group’s brainy member; and Shaggy Rogers (Casey Kasem), their ever-hungry and ever-terrified friend.