Mystery Inc. has cracked the case to top all cases! They�ve tracked down Coco Diablo, the head of a notorious costume crime syndicate. With Coco and her kitty in prison, Mystery Inc. thinks that they can finally enjoy a break. Wrong! Suddenly, menacing doppelg�nger ghosts of the Scooby crew and favorite classic foes show up in Coolsville to threaten Halloween. Now it�s up to the meddling kids to unmask the latest scoundrel and save Halloween!