A reconstructed English castle including the ghosts of Merlin The Magician and The Black Knight is the setting for an adventure in which Scooby and the kids track down 20th Century jewel thieves in an 18th Century romp. Shaggy Rogers’ Uncle Shagworthy, kooky zillionaire and one of the world’s biggest jewel dealers, takes a liking to an Old English castle so much he has had it imported to the U.S.A. stone by stone- but it also becomes his undoing when he disappears! While searching for him, the kids and Scooby have a run-in with ghosts of The Knights Of The Round Table. In the confusion Shag and Scooby fall into the clutches of The Black Knight and brought to Merlin who, via mesmerizing, makes them his evil apprentices and has them do away with their “former friends”…a task which Shag and Scooby, fortunately, botch twice. Velma deduces they have been mesmerized and manages to un-mesmerize them with (of all things!) a Scooby Snack. Uncle Shagworthy is found chained up in the dungeon, and The Black Knight and Merlin are captured in a tapestry; upon pulling off the disguises, they are revealed to be, respectively, a hired henchman and Zarko The Magician (whose saw-em-in-two act Shag and Scooby managed to ruin earlier).