Then -- The mystery is solved!
You go: that's it?
John Steinbeck in his travels across the U.S. with his giant blue poodle, Charlie, forever got lost.
As he stared forlornly at maps, he learned a valuable lesson that applies to novel-writing:
To find where you are going, you must first know where you are.
HOW TO TRIANGULATE YOUR ENDING -
I. Your hero is the catalyst -
His nature stirs the pot. He does not sit and whine and narrate others helping him out. He steps up to the base and swings.
If God walks in, rolls up His sleeves, and says, "Looks like you could use some help" --
It is your ending that needs the help!
II. Lessons learned come into play:
Your hero's lifelong problem/inner demon makes a last ditch effort to derail your hero's life.
But your hero has grown and side-steps his inner demon, using the strength he has acquired along the way.
III. The hero is new-born, forged in the crucible of the prior pages.
The hero should demonstrate courage, creativity,
even brilliance in setting the cogs in motion that
will resolve the story.
This is where the protagonist earns the right to be called a hero.
Here’s the real magic of THE ENDING:
If you’ve done your job well in the first three quarters of your story,
if you’ve plotted with powerful milestones that are in context to a compelling and empathetic hero’s quest and evolving arc,
chances are you’ll intuitively know how your story needs to end when you get there.
Or, if not intuitively, then after some serious introspection and long walks in the woods with a digital recorder!
THE ONE RULE THAT MUST NEVER BE BROKEN!
No new expositional information may enter the story once it has been triggered.
If something appears in the final act,
it must have been foreshadowed, referenced or already in play.
This includes characters.
You should strategize and plot all your main story points beforehand—
even if you aren’t yet sure of your ending—
and in the process of developing the first three parts
you’ll find that the final act begins to crystallize as part of the process.
I hope this helps in some small way.