While babysitting a child, Daphne and the child Arthur were attacked by a flute playing creature, and Arthur became a werewolf-creature. The adults in town love the tourist attraction. The gang want to help, but are taken to school by Sherrif Stone and Mayor Jones. During lunch at school, Velma wants Shaggy to stop staying like. She picks out some new pants for him. A small intelligent kid named Mary Anne Gleardan, who is supposed to be college, must tutor Fred in civics. Dr Portrillo, a new teacher thinks he is Que Horrifico. The gang watch him at his home. He is not the monster after all, The gang disguise as a family at an abondened house. Que Horrifico strikes. They trap him....who is a her, Mary Anne Gleardon. She wanted the town clear of adults so that she could run the city. The kids just dressed up for some candy. Shaggy gets into his original pants again, and the gang party at the radio station.