Simply put, the climax is the moment of crisis when the protagonist has no way out and has to make a decision or act in such a way to reach the story goal. Up to this point, the reader has observed the hero struggle to reach the story goal and is familiar with his particular behavior or pattern of problem solving. It's this personality trait that either helps or hinders him.
|Deckard barely hangs on in Blade Runner|
photo credit, atthelighthouse.blogspot.com
Think 'danger and opportunity'. Our hero has to make a decision to save the story goal, but we don't know if it's the right one until the very end. All we know is that he's doomed if he does nothing, but at the same time there's an unseen/unexpected potential for growth or new beginning.
Depending on how you want your story to end, helps determine what questions or issues need clarifying. Once you've established what should be answered, imagine an extensive, irreversible event that will force those issues to be addressed.
Like bacteria that continue to live and grow, your protagonist should have evolved from who he was at the awesome beginning that hooked us in the first place. It's imperative to show how our hero's behavior is challenged by pursuing the story goal. Ultimately, it's the decision the hero makes in the end that leads to personal growth and showcases the moral or theme of the story.
A reader will invest hours of time into your novel, make sure their last impression is the greatest one.
Next week, I'll be blogging how to nail your ending.