Mr and Mrs Brown have a huge family of incredibly naughty children. They had once been fortunate enough to acquire the services of Nurse Matilda, who had transformed the children into models of good behaviour. But now the children have slipped back into their wicked ways: Tora has put glue in the sandwiches - Emma has made a chocolate cake out of mud - David has put a toad in the milk jug - and Tim is tying Nanny's shoelaces to her chair! Their stay in London with their Great Aunt Adelaide seems set for disaster - until the arrival of Nurse Matilda...