Vincent's monitor of spirit world activity reveals that Marcella, an escaped demon, has given the three inept Brewster sisters The Black Book of Spells and instructions to cast spell number thirteen at Stonehenge at midnight. While Scooby and the gang follow the sisters to the ends of the earth trying to nab the spellbook, Vincent goes to the Zone of Eternal Evil -- where he quickly befriends a small creature named Idesvigg and is subsequently captured by Marcella.