him to a nearby cemetery. He rescues Shaggy from some monsters, before discovering Daphne held hostage by The Mastermind. The Mastermind proceeds to summon the Green Ghost, which attacks Scooby with green fire and electricity. Scooby is able to contain the Green Ghost with Daphne's help. Suddenly, Holly emerges from the brush. She and Daphne fall through a concealed door when Daphne rests against a tombstone, leaving Scooby alone once again. He uses a newly acquired invention, an umbrella, to explore a chain of old shipwrecks. Eventually, Scooby discovers Fred imprisoned in one of the ship's brigs, where he is confronted by The Ghost of Redbeard. He attacks Scooby by summoning numerous ghosts, but Scooby is able to smash him by dropping a treasure chest on his head. Velma arrives, still claiming to be chased by the Creeper. Fred discovers an image of the monster stamped on her glasses, and they head off to search for Graham's concealed laboratory. Meanwhile, Scooby and Shaggy indulge themselves with food, but Shaggy is scared off by The Ghost of Captain Cutler. Scooby acquires another of Graham's inventions: bubblegum, which he uses to trap monsters from being able to attack him. Scooby makes his way back to the overhangs, where he begins navigating the dungeons under the mansion. He encounters numerous ghosts, which he is able to destroy and avoid using his newly acquired inventions: air-bubbles. Scooby eventually discovers Professor Graham's laboratory, which has become overrun with monsters, namely the Funland Robot and the Space Kook. Scooby rescues Shaggy from being eaten by a shark, before continuing onward into another room, where he reunites with the rest of the gang and Holly. Fred reveals that the ghosts are entirely fake: The Mastermind has been using holographic images of monsters and ghosts from their past to terrorize them. He constructs a plan, which calls for Scooby to distract The Mastermind. Scooby fights and defeats The Mastermind, stunning him. He is sucked up through a tube which spits him out in the mansion's parlor. The gang and Holly make their way back to the first floor of the mansion. They unmask The Mastermind, only to discover Professor Graham in the costume. Velma argues that none of the clues make sense, before holding her glasses up to a mirror. The light reflected off the glasses and mirror reveal Holly operating a control panel behind a holographic wall.