peripeteia

noun3

1. •
   A sudden reversal of fortune as a plot point in Classical tragedy.
2. •
   Any sudden change in circumstances; a crisis.

   • Once more I was a man in a myth, incapable of understanding it, but somehow aware that understanding it meant it must continue, however sinister its peripeteia. — 1965
3. •
   A turning point in psychosocial development.