Lisa Cron in Wired for Story on page 130, uses the analogy of earthquake fissures that lead to the big one in the life of the protagonist. The “first hairline crack and its resulting offshoots are like fault lines, running through the center of the protagonist’s world, undermining everything. As with an earthquake, the cracks tend to be caused by two opposing forces, with the protagonist caught between them.”
What is the first hairline crack in your story that starts the ultimate change in your protagonist’s life?