Hope is beginning to lose her grip. She has three unruly children (well, four if you count her hopeless husband), a high-powered job in real estate on Long Island that keeps her permanently stressed and overworked, a glamorous ex-husband who she is still in love with and a serious nanny crisis. The fifth childminder in nearly as many weeks has walked out and, today of all days, when she has a 1.5 million dollar house to sell, she is left holding the baby - literally.

In desperation, Hope calls England and asks her sister-in-law to send Mary Poppins. Instead she sends Annabel and Annabel isn't quite what Hope had in mind - she has had very little experience with children, she hardly knows anything about babies, she cannot drive and the real reason she has come to America is to escape her own problems.

But miraculously Annabel becomes the answer to everyone's prayers: the children become less unruly, the husband becomes less hopeless, the ex-husband is suddenly less glamorous and Hope begins to regain control of her life. But why was it that Annabel left England in such a hurry? And now that she has solved everyone else's problems what about her own?