counterturn

noun2

1. •
   A turn in the other direction; one of the turns of a zigzag.

   • Every turn, every spiral, every extension eventually has to be tempered by a counterturn, a counterspiral, or a flexion; sometimes strong, sometimes subtle. — 2010
2. •
   The critical moment in a drama, when, contrary to expectation, the action is embroiled in new difficulties.