^Shouldn't use "Should know" when ^ doesn't know if < (or anyone) already knows or not
And if I recall correctly, the plot is "girl who turns into granny seeks help from wizard, and through a series of events manages to change back eventually". The book's plot, on the other hand, is "girl turns into granny, seeks help from lecherous wizard (Miyazaki toned that part down a bit), and through events kills (or maybe it was just defeats) the witch who turned girl into granny".
Miyazaki did alter the story a bit, but he still did it in a way that it turned out well.