The Scooby Gang (Fred, Daphne & Velma) return in this episode.Dr. Phineus Phibes develops a stealth device (an invisibility ray) and renders Agents 1 & 2 invisible so they can travel to a top secret government weapons facility and steal a deadly disintegration ray.  After searching for Phibes' cloud ship and getting sidetracked by a stowaway sheep and a trip to get ice cream (which they share with the sheep), Scooby and Shaggy show up at the weapons facility to foil Phibes' agents. To Scooby and Shaggy’s surprise, they find the old gang (Fred, Daphne and Velma) already on the case. The old gang is at the facility investigating a "ghost report," but Scooby and Shaggy set them straight, explaining that the "ghosts" are actually Phibes' invisible agents. With Scooby and Shaggy leading the way and the whole gang working together, Phibes is foiled again and the world is safe for another day.