The Banks children, Jane and Michael, change nannies just about as often as most people change their clothes. It's not that they're naughty, exactly - just awkward. Everyone in the household is at their wits' end with them - until Mary Poppins arrives.

In the oldest part of Stockholm, Bell Everhurst is working as a nanny for an affluent family. Hanna and Max Mogert are parents to seven-year-old Linus and five-year-old twins Ellinor and Tilde, and Bell has been with the family for over two years. One early Spring morning, as she's rushing out to take the children to school, she answers the phone - and everything changes. A woman from a clinic she's never heard of asks her to pass on the message that...