Walt Disney's attempts to get PL Travers' permission to make Mary Poppins is a wonderfully simple story.
She can't stand animation, bad grammar, pears, fun, over familiarity and a hotel room full of his stuffed Disney toys.
He's used to folks melting at his excess charm and charisma, not pedantic British authors who resist lucrative offers to adapt their work for the big screen.
It's a great tale, beautifully told, even if the flashbacks of Travers' youth in 1907 Australia are problematic.
Her dealings with an alcoholic dad (Colin Farrell) and suicidal mum (Ruth Wilson) keep dragging us out of the joy of Emma Thompson's performance as Travers and Tom Hanks' beautiful turn as Disney, mostly in 1961.
Around a third of the film is made up of Australian scenes, and the problem is every time Em and Tom's storyline builds up a head of steam, it's diffused by moments involving Colin, Ruth and their screen family emoting Down Under.
Ruth is as glorious as ever, though she is in danger of being typecast by Disney Studios as the long suffering homestead housewife usually pegging out washing in period dramas. See also their much maligned The Lone Ranger movie.
(Aside from the fact she's magnificent in Luther, Ruth has perhaps the most expressive eyebrows of any actress. Let's hope she gets the leading role she deserves at some point).
The supporting cast is great, especially Bradley Whitford as Mary Poppins co-writer Don DaGradi, and Paul Giamatti as Travers' jovial driver, Ralph.
The latter and Emma would have made a great movie on their own, Driving Ms Travers if you like.
SMB is rounded out by a superb sucker punch finale, and yet another gobsmacking turn from Hanks.
I'd thought Tom had lost his lustre as one of the world's most likeable A-listers, but after the double whammy of this and the jaw-droppingly tense Captain Phillips, safe to say he's regained his throne.
As for Emma? Well, it's Emma Thompson. She's never given a bad turn in anything, and after more than 20 years on the big screen, she just gets better with each performance.
I had feared this was going to be a predictable, button-pushing Disney advert, but because the back story has such heft, it's hard not to be drawn in.
Yes, buttons are pushed, but so subtly, a simple thing like Giamatti arriving to pick up Em can leave you blubbing.
More Tom and Em, less Oz and this would have a five star masterpiece instead of a four star gem.
However, Saving Mr Banks is still a tear-jerking, feel good, surprisingly dark Christmas cracker.
Practically perfect in (almost) every way.