plot twist vs whim

plot twist

noun
  • A change in the direction or expected outcome of the plot of a film, novel, or other narrative work. 

whim

noun
  • A fanciful impulse, or sudden change of idea. 

  • A bird, the Eurasian wigeon. 

  • A large capstan or vertical drum turned by horse power or steam power, for raising ore or water, etc., from mines, or for other purposes 

verb
  • To be seized with a whim; to be capricious. 

How often have the words plot twist and whim occurred in a corpus of books? (source: Google Ngram Viewer )