The sisters build a witches' computer to tell them how to do even more wicked deeds, and Wendy tries to find a way to render it useless.; Elmer gives Wendy several new brooms but they turn out to be too powerful to use.; Casper helps a friendly dog find a new master.; The sisters try to flee their home during Visiting Witches' Week so they won't be bothered by unwelcome guests, but they are too late.; Velma is afflicted by the Running, Hopping, and Whooping Hex.; Bratty-Lou pesters Wendy to go broom riding with her.