about-face vs plot twist

about-face

noun
  • A reversal in direction; a reversal of attitude or opinion. 

  • An abrupt turn to face the opposite direction. 

verb
  • To turn 180 degrees to face the opposite direction. 

  • To change opinion or attitude drastically. 

plot twist

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

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