AThree books, actually. Emma Thompson adapted a series of three Nurse Matilda books (Nurse Matilda (1964), Nurse Matilda Goes to Town (1967), and Nurse Matilda Goes to Hospital (1974)), all written by British children's author Christianna Brand [1907-1988]. Thompson wrote the screenplay for Nanny McPhee and plays the title character in this film and in a sequel, Nanny McPhee and the Big Bang [aka Nanny McPhee Returns] (2010).
AThe day of the wedding quickly approaches. Selma (Celia Imrie) has decorated the garden to suit her fancy pink and green arrangement and dressed the children to look like green and pink shepherds and shepherdesses. Aunt Adelaide (Angela Lansbury) arrives along with Evangeline (Kelly Macdonald) and, after introductions, everyone takes their places. As Selma walks up the aisle, she turns to the children and whispers, 'Behave!' Baby Aggy (Hebe Barnes) and (Zinnia Barnes) repeats the word, but it comes out sounding like 'Beehive.' Nanny McPhee reminds Simon (Thomas Brodie-Sangster) that he must do exactly as he's told, and an idea comes to him. He starts buzzing and swatting at imaginary bees until everyone is also swatting at the no-see-ums. In a panic, the minister swats at a cake, sending it hurling into Selma's face. Selma grabs a tart to toss back at the minister, but he ducks and it hits Aunt Adelaide instead. Soon, everyone is tossing tarts at each other. Much to Aunt Adelaide's dismay, even Evangeline joins in laughing and tossing. Selma admonishes the children, but Cedric (Colin Firth) admonishes her, so Selma calls off the wedding. Aunt Adelaide admonishes Cedric and walks away. Suddenly, Simon has another idea. He reminds Aunt Adelaide of her promise to support them if his dad marries within a month. The children suggest that he marry Evangeline. Cedric and Evangeline admit that they love each other. Nanny McPhee, her face now wartless and the snaggletooth gone, taps her stick, and it starts to snow, covering all the pink and green stuff with white. Evangeline's blue-and-pink dress changes to a white wedding gown. In the final scene, Cedric and Evangeline are married, a new rattle drops from the sky into Baby Aggy's lap, and Nanny McPhee walks away. In a voiceover, she says, 'When you need me and do not want me, then I will stay. When you want me but no longer need me, then I have to go.'
AWhen they learn to go to bed when they are told (and say please), her hair goes from gray to brown. When they learn to get up when they are told, the wart near her nose disappears. When they learn to get dressed when they are told, the wart on her jaw disappears. When they learn to listen (and say thank you), her uni brow disappears, her hair turns blonder and wavy, her droopy earlobes disappear, and her complexion improves. When they finally learn to do as they are told, her nose is no longer bulbous and the snaggle tooth disappears.