布朗(科林•菲尔什 饰)的妻子在一年前去世,留下了七个古灵精怪的孩子。整天在工作上疲于奔命的布朗,回到家里还要应付这些捣蛋鬼。为此,布朗前前后后找了16任保姆,可没有一个能应付这些鬼精灵。雪上加霜的是,布朗专横的姑妈向他下了最后通牒,如果他不能在一个月内再给孩子们找到一个母亲,就不再资助他们生活费。负债累累的布朗如果得不到姑妈的资助,就很可能会锒铛入狱。此时,生活陷入绝境。 正在布朗感到绝望的时候,一个长相极为丑陋的女人出现在他家门口。女人告诉布朗她叫南茜•麦克菲(艾玛•汤普森 饰),并毛遂自荐当上孩子们的保姆。麦克菲拥有神奇的魔力,无论孩子们怎么计划好要戏弄她,都无法成功。孩子的恶作剧有时甚至会报应在自己身上。在麦克菲的细心的调教下,孩子们一天天变乖,而布朗的处境也日益好转,就连魔法保姆自己的面容,也在发生变化…This is a Story of a man named Cedric Brown, and his 7 children that do everything to get ride of 17 nanny's. One night when the kids are in the kitchen when there went suppost to, that was the night that Nanny McPhee appeared. She goes into the kitchen to find that the children are messing with everything in the Kitchen. Nanny McPhee tells them to stop, but the oldest says not to. Nanny McPhee banged her stick and threw kids kept going non stop until Simon said "Please Nanny McPhee". She stopped and everyone went to bed. The next day they were in bed all day because they were "sick". But they lied so until they said Please and thank you they were able to get up. They learned their own lessons and until the end the have learned their lessons and Nanny McPhee left. She said herself "When you need me, but don't want me then I must stay. If you want me, but you don't need me anymore, than I must go." This is a lesson of Obeying your adults and leaders.l, or she might get you.