When Jane (Karen Dotrice) and Michael (Matthew Garber), the children of the wealthy and uptight Banks family, are faced with the prospect of a new nanny, they are pleasantly surprised by the arrival of the magical Mary Poppins (Julie Andrews). Embarking on a series of fantastical adventures with Mary and her Cockney performer friend, Bert (Dick Van Dyke), the siblings try to pass on some of their nanny's sunny attitude to their preoccupied parents (David Tomlinson, Glynis Johns).