Nanny McPhee is the hilarious and heartwarming story of a magical nanny who is hired to tame the seven most mischievous children in the history of the world.

Emma Thompson portrays the mysterious Nanny McPhee, a person with unsettling features and magical powers, who enters the household of the recently widowed Mr. Brown, played brilliantly by Colin Firth, to look after his dreadfully-behaved children.

The children have managed to drive away seventeen previous nannies and are certain they'll have no trouble getting rid of this one too. But as Nanny McPhee takes control, the children begin to notice that their acts of mischief lead swiftly and magically to unexpected consequences. Is she a hypnotist? A magician? A witch? Even Mr. Brown isn't sure, but he can't help but notice that under Nanny McPhee's influence, his own life is being turned upside down as well.

Her influence also extends to the family's deeper problems, including Mr. Brown's sudden and seemingly inexplicable attempts to find a new wife; an announcement by the domineering Aunt Adelaide (Angela Lansbury, who makes a welcome return to the big screen after an absence of two decades) that she intends to take one of the children away. As the children's behavior begins to change, Nanny McPhee's arresting face and frame appear to change as well, creating even more questions about this mysterious stranger whom the children and their father have come to love.