Scooby Doo, Shaggy, Daphne, Velma, Fred, and the Mystery Machine are
vacationing in Australia. After sight-seeing in Sydney, they head for the
Outback to attend the Vampire Rock Music Festival. Legend says that
Vampire Rock is the home of the Yoweeyahoo, an ancient Australian vampire.
The events of last year's festival are making Malcolm, Daniel, and co-promoter Russell very nervous. Following the festival, one of the bands called Wild Wind went camping on Vampire Rock and were never heard from again. Rumor has it that all three were kidnapped by the Yoweeyahoo and turned into vampires. Now, strange things are happening at this year's festival--sounds, lights, and smoke are issuing from Vampire Rock. And last night three vampires (who look like the members of Wild Wind) swooped down and carried off the band members of Matt Marvellous. Most of the finalists have pulled out of the contest and are going home.
When Scooby and his party arrive at Vampire Rock, they are warmly greeted by their friends, the Hex Girls, who are scheduled to open the show. Sensing a mystery to be solved, Fred, Daphne, and Velma decide to form a rock group themselves and go undercover as The Meddling Kids.
Next band to arrive is the Bad Omens and their rather shady manager, Jasper Ridgeway. Fred immediately suspects them, as Jasper Ridgeway also managed Wild Wind. Fred, Daphne, and Velma go nosing around Jasper's motorhome, where they find the costumes worn by Wild Wind. Scooby and Shaggy are chased by the three vampires, who also show up during rehearsals and carry off The Bad Omens. That night, Russell's pick of the show--Two Skinny Dudes--arrive, and Jasper immediately offers to be their manager.
It's finally the night of the festival. The Hex Girls start playing but, during their performance, they too are kidnapped by the three vampires. In search of The Hex Girls, Scooby and company climb Vampire Rock where they find a secret passage that leads into a cave holding a lot of stage equipment. Enter the Yoweeyahoo and the three vampires, leading to a long chase around the mountain. When the morning sun breaks over the horizon, the Yoweeyahoo disappears in a puff of smoke, but the vampires still persist. The sun doesn't seem to harm them, and running water doesn't stop them either.
Eventually, Daniel traps the three vampires in a net, and the identities under their vampire masks are revealed. It's The Two Skinny Dudes and Russell. No, wait! Pull off their second masks, and it's really Wild Wind. They had planned from the beginning to scare away all the other bands, leaving just The Two Skinny Dudes who would also disappear during their performance to be followed by Wild Wind's triumphant return. They figured the publicity would make them famous.
The Yoweeyahoo, by the way, turns out to have been a hologram created by all the stage equipment found in the cave. [Original synopsis by bj_kuehl]