context: The film takes place in Australia, where the "Vampire Rock Music Festival" is being set up near Vampire Rock, a rock formation shaped like a vampire head. There is a legend of a vampire named the Yowie Yahoo, who lives in the rock. Many people are excited for the event, but some don't think it should take place because it would anger the Yowie Yahoo. One such person is Malcolm Illiwara, even though his grandson Daniel is the manager of the contest. One night, as Malcolm and Daniel watch a sure-to-win performer named Matt Marvelous, the Yowie Yahoo appears. The Yowie Yahoo and its three vampire minions capture Matt Marvelous and take him away. Everyone is scared, and Malcolm blames the contest for what happened.
  Meanwhile, Scooby-Doo and the Mystery Inc. have arrived in Australia for a vacation after solving the mystery of the Sea Serpent Smugglers on a cruise ship. After seeing the harbor, the gang decides to go to the outback and see the music festival. When they arrive, they meet the Hex Girls, (the band the gang had met before in Scooby-Doo! and the Witch's Ghost) who are the opening act. They also see Daniel, Malcolm and Daniel's partner Russell. Malcolm tries to warn Daniel about what has happened and drives off. Daniel tells them that most of the performers have left because they are too scared of the vampires. Daniel and Russell then tell them about Wildwind, a musical group who performed at the Vampire Rock Music Festival the year before. Though Wildwind put on a great performance, they only got third place. They then went into Vampire Rock to camp but were never heard from again. It is believed that the members of Wildwind - Dark Skull, Stormy Weather, and Lightning Strikes - have been turned into vampires by the Yowie Yahoo. Daniel says he does not believe it, but then Russell reminded him that the three vampires who were with the Yowie Yahoo when it kidnapped Matt Marvelous looked just like the members of Wildwind.
  Fred decides the best way to solve the mystery is to enter the contest as a band, in order to drive the Yowie Yahoo to capture them. Russell is skeptical, but Daniel thinks it is a good idea. The Hex Girls make them look like rock stars, and soon they are on stage. While they are practicing (but not very well), a golf cart approaches them. In it are Jasper Ridgeway, a snotty manager, and his band, the Bad Omens. They criticize the gang's playing and make them leave the stage so they can practice. Then the gang learns that Jasper was once the manager of Wildwind. Jasper says Wildwind was the greatest band he ever managed and is still haunted by their disappearance. He then complains about the head and camping, and goes back to his trailer, leaving his band to practice. The gang grows suspicious of Jasper and thinks he might have put his band up to masquerading as vampires and getting rid of all the other performers. They split up, with Fred, Velma and Daphne going to Jasper's trailer and Shaggy and Scooby staying at the food stands.
  At the trailer, Fred, Velma and Daphne find that Jasper has lots of mementos of Wildwind, including the band members' old stage costumes. They also wonder why Jasper did not come to his trailer, (as they have been there); when he said he was going to. Meanwhile, Scooby and Shaggy get chased by the Wildwind Vampires but eventually lose them. They end up back at the stage, where the Bad Omens are rehearsing. There, they witness the Yowie Yahoo and the Wildwind vampires capture the Bad Omens is the same way they captured Matt Marvelous. They tell the others. Jasper is sad they are gone, but then he says he shouldn't have gone back to his trailer, when in fact he was never there at all. Fred decides that everyone should sleep at the same place, so no one gets taken.
  During the night, a band named Two Skinny Dudes arrives. They say they have been staying in Vampire Rock, but have not seen any. Jasper quickly forgets the Bad Omens and asks Two Skinny Dudes if they wanted him to be their manager, which makes the gang suspicious. The next day, the gang and Daniel go to see Malcolm. He explains how Wildwind was foolish to go into Vampire Rock. He also says how vampires hate the sun, cannot run over running water, and cannot be seen in a picture. Later that night, the Hex Girls start things off. However, the Yowie Yahoo and the Wildwind vampires appear and capture the Hex Girls. The crowd thinks it was an act, but the gang decides to investigate the rock.
  Inside, Fred, Velma and Daphne find lots of special effects equipment like fans and lights. However, they find the Wildwind vampires and get chased. Scooby and Shaggy get trapped by a group of dingoes. The sound of Fred, Velma and Daphne running scares off the Dingoes, but then the whole gang gets trapped by the vampires and the Yowie Yahoo. The gang is able to avoid them until the sun comes up. The sun reflects off Scooby-Doo's collar, which shines on the Yowie Yahoo and destroys him. However, the Wildwind vampires are not affected by the sun or running over water, and give chase to the gang. The Wildwind Vampires chase them until the gang and Daniel unleash a trap and capture the "vampires". Jasper and Daniel are confused, but the gang knows. After splashing water on the faces to get rid of the makeup, the gang shows that it was Two Skinny Dudes and Russell. Daniel and Jasper are surprised, but get even more surprised when the gang unmasks them and it is shown that the members of Wildwind are the actual vampires. They explain how they wanted to start up their career, so they posed as dead and were planning to perform again. They used special effects to make the Yowie Yahoo and climbing equipment to fly around. When asked about the missing performers, they said they sent them away on free Great Barrier Reef Scuba diving tours. Then the Hex Girls and Malcolm show up. The Hex Girls say they were left in the Outback because they did not want the trip, but Malcolm found them.
  The members of Wildwind are arrested and sent to jail. Daniel realizes that since all the other bands are out of the competition, that makes Scooby and the gang the winners by default. The film ends with the gang performing to the crowd and getting their band name, the Meddling Kids, joined by the Hex Girls.
question: Which act is kidnapped during their performance?
answer: Matt Marvelous