They think Jeremiah Wickles ( Peter Boyle), the original Black Knight, is behind the case, so they go to his mansion. Velma believes that one of their old foes is behind the case. Shaggy and Scooby decide to help the others more by acting like real detectives. Things turn bad for the gang, as Heather-Jasper Howe ( Alicia Silverstone, a newsreporter is grudging against them.

After the robbery, Velma discovers a reptillian scale and finds out it is made or randomonium. The Pterodactyl Ghost snatches the costumes of The Black Knight Ghost and the 10,000 Volt Ghost and flies away with the Evil Masked Figure. that he will unmask them as the true buffoons they are. A villain name the Evil Masked Figure appears, warning Mystery Inc. try to trap it in some curtains, but the pterodactyl breaks free and flies around the museum, taking Scooby and Shaggy with it, who have accidentally caught their hands in some ropes. Believing it is a guy in a costume, Mystery Inc. The opening is turned from a pleaseant evening into a living horror movie, when the costume of The Pterodactyl Ghost becomes a real prehistoric predator and goes on the rampage. The museum is owned by Patrick ( Seth Green), who Velma has fallen in love with. They are attending the grand opening of the Coolsonian Criminology Museum, where there is an exhibit featuring costumes from the villains Mystery Inc. Scooby-Doo, Shaggy, Fred, Velma and Daphne have become celebrities in their hometown of Coolsville, after solving the mystery on Spooky Island. Meanwhile, brainy Velma (LINDA CARDELLINI) becomes smitten with another key suspect, Coolsonian Criminology Museum curator Patrick Wisely (SETH GREEN), as macho leader Fred (FREDDIE PRINZE JR.) and image-conscious Daphne (SARAH MICHELLE GELLAR) attempt to determine the identity of the Evil Masked Figure whose monster army is wreaking havoc on Coolsville.Spoiler warning: Plot or ending details follow. Did the creepy wannabe launch the monstrous attack on Coolsville in a diabolical quest for revenge? All signs point to Jeremiah ?Old Man? Wickles (PETER BOYLE), the former Black Knight Ghost who was once unmasked by the gang and thrown in jail. The ever-ravenous duo, determined to prove they?re great detectives, don a series of far-out disguises in their search for clues. Under pressure from relentless reporter Heather Jasper-Howe (ALICIA SILVERSTONE) and the terrified citizens of Coolsville, the gang launches an investigation into the mysterious monster outbreak that leaves Shaggy and Scooby questioning their roles in Mystery Inc. foes like The Pterodactyl Ghost, The Black Knight Ghost, Captain Cutler?s Ghost and The 10,000 Volt Ghost.

Jinkies! In Scooby-Doo 2: Monsters Unleashed, Scooby and the gang lose their cool ? and their stellar reputation ? when an anonymous masked villain wreaks mayhem on the city of Coolsville with a monster machine that re-creates classic Mystery Inc.

Cast of scooby doo 2 monsters unleashed