Does the Loch Ness monster exist? The Mystery Inc. gang -- Scooby-Doo, Shaggy, Daphne, Velma and Fred -- take on this decades-old puzzle in another wild and wacky animated adventure. The gang heads to a castle in Scotland owned by Daphne's family to decipher the clues, which at first point to the creature's existence. But as always, things are not what they seem. Along the way, Scooby and Shaggy get spooked by ghosts and goblins galore.