Isabel Green has three children who don't stop fighting, her husband is away at war and leaving her running the family farm, that her brother in law urges her to sell , and in the face of all these pressures, it's inevitable to use nanny McPhee, and a little magic will ensure her happiness.
Mrs. Green (Maggie Gyllenhaal) is going crazy trying to keep up with everything. Among her tasks are a farm that has to be maintained, a job at a shop in town and three unruly children that have to be looked after, not to mention the fact that her husband can’t because he is away at war. Faced with all these pressures Mrs. Green has no choice but to enlist the help of Nanny McPhee (Emma Thompson). A little magic goes a long way with regards to helping Mrs. Green keep everything in order.