An act earns momentum by making the next choice harder than the last.

McKee frames the middle movement of story as progressive complications: a sequence that runs from the Inciting Incident toward the final Crisis/Climax. The point is not that a screenplay must display a prescribed number of acts. The point is that the protagonist's pursuit keeps meeting resistance that makes the original plan insufficient.

That definition transfers cleanly to any narrative with a decision at its center. If the next scene, beat, email, or product moment simply restates the first problem, the sequence is busy but static. The reader should be able to name what has changed in the situation and why the old answer is now too small.

McKee's first mechanism is the gap between expectation and result. A character acts to restore balance, the world reacts in an unforeseen way, and the gap signals that the initial effort will not work. The response must therefore draw on greater willpower, capacity, risk, or invention.

This is why he calls the progression a movement through points of no return. The reader does not need a louder incident; they need to see that a lesser action has become implausible. A story advances when the choice narrows because something meaningful has already happened.

McKee warns against retreating to actions of lesser quality or magnitude. The writer cannot preserve momentum by repeating a version of the move that already failed. Each new attempt must enter a more demanding level of conflict and push toward a final action beyond which the audience cannot imagine another.

For commercial storytelling, this is a useful test for a launch sequence or case study. Do not add more claims merely to prolong attention. Let a proof point create a new question, let that question reveal a real constraint, and make the next proof answer the higher-stakes objection. The sequence should earn its escalation.

McKee calls conflict the soul of story because it makes time feel consequential. But he also distinguishes meaningful conflict from spectacle for its own sake. Opposition matters when it is honestly tied to a desire, a scarcity, or a force that can block the character's attempt to restore balance.

The practical question is therefore not, 'How can I make this more dramatic?' It is, 'What force would make the desired result genuinely harder, and what changed action would meet it?' That question protects a narrative from both flat harmony and arbitrary chaos.

McKee closes by examining the relationship between a central plot and a subplot. Their strongest use is not mere variety. They can create contrast, deepen a controlling idea, raise a pressure that the central plot cannot express alone, or mirror the same dilemma on another plane.

Use that standard when you add a supporting thread to a narrative. If removing it leaves the central choice unchanged, it may be ornament. If it reframes the central desire, sharpens a contradiction, or makes the ultimate choice costlier, it belongs in the design.