The story's center hinge — a reversal or revelation that changes the game rather than marking time.
A working midpoint is not 'the middle' but a turn: a false victory that will curdle, a false defeat that will invert, a reveal that reframes the goal. It typically flips the protagonist from reacting to pursuing — or raises the stakes so the old plan dies.
Sagging second acts almost always trace back here: without a real hinge at the center, pages 45–75 become variations on a theme instead of escalation.
Go deeper: Save the Cat! — beat sheet