blind alley vs mischance

blind alley

noun
  • Used other than figuratively or idiomatically: see blind, alley. A street or passageway that leads nowhere. 

  • A course of inquiry that leads nowhere. 

mischance

noun
  • A mishap, an unlucky circumstance. 

  • Bad luck, misfortune. 

verb
  • To undergo (a misfortune); to suffer (something unfortunate). 

How often have the words blind alley and mischance occurred in a corpus of books? (source: Google Ngram Viewer )