Mr. and Mrs. Twit are a pair of hideous, spiteful people who live in a windowless house and spend their time playing nasty practical jokes on one another. Mr. Twit is famous for his disgusting, unwashed beard filled with old food, while Mrs. Twit uses her glass eye to spy on him. Their cruelty extends to their pet monkeys, the Muggle-Wumps, whom they force to stand on their heads all day. Eventually, the monkeys and a visiting Roly-Poly Bird team up to take revenge on the terrible couple in a brilliantly sticky and clever way.