Spurred on by a promise he made to his daughters, Walt Disney (Tom Hanks) embarks on what would become a 20-year quest to obtain the movie rights to "Mary Poppins." The author, P.L. Travers (Emma Thompson), proves to be an uncompromising curmudgeon who has no intention of letting her beloved characters become mangled in the Hollywood machine. However, when the books stop selling and she finds herself in need of money, Travers reluctantly agrees to consider Disney's proposition.