Velma tracks the signal from the device to the Rock 'n' Roller Coaster Land amusement park where a man named Alvin Wiener informs the gang that a masked musician, the Guitar Ghoul, has scared off all the other guests. Scooby finds clues that tell of disturbing events (rides going havoc, animatronics chasing people, etc.). In time, Shaggy falls down a slide, promoting Scooby to save him. After a scare from the Guitar Ghoul, the two meet Nikki Starlight, who claims to be the Guitar Ghoul's girlfriend. Afterward, Daphne is trapped in a cage in a circus tent and is saved by Scooby in a new gliding costume. Regrouping, the Guitar Ghoul mocks the gang, as Scooby finds his location in a house of mirrors and defeats him. The Guitar Ghoul is revealed to be Alvin, as Velma reveals that he is really a failed musician who blamed the Guitar Ghoul for ruining his career. Nikki reveals herself as the real Guitar Ghoul, having done so to keep her private life secret. Velma tells Scooby to smell Alvin's costume, revealing it to be Mubber as Alvin admits he doesn't know the name of the person who gave him the suit. Nikki thanks the gang for saving her reputation and tells them to go to a private natural history museum where M.F.M. worked on some of the exhibits.