By P.L. Travers, the author featured in the movie Saving Mr. Banks It all starts when Mary Poppins is blown by the east wind onto the doorstep of the Banks house. She becomes a most up banisters, pull an entire armchair out of an empty carpetbag, and make a dose of medicine taste like delicious lime-juice cordial? A day with Mary Poppins is a day of magic and make-believe come to life!