Okay, so you're back for part three! This is Book Three. (You can see my posts about writing a trilogy, part one and part two.)
So Book Three, in my experience, is The War. Plain and simple. You've set up what's wrong with the world/MC in Book One. You've explored what they're going to do to fix the world/themselves in Book Two. And now it's time to DO IT.
It's the end conflict, and everything has to come to a head by the end of the book.
Think of the trilogies (or series) you've read. I'm thinking of The Hunger Games, The Forest of Hands and Teeth, and Harry Potter.
Think about what happens in the last book. Basically, your main character overcomes all their shortcomings, figures out the mysteries, solves the puzzles, and prevails over the villain.
Sounds easy, right?
Sure, it sounds easy. But it's really hard to actually do.
Here are a few things that will hopefully help you along your way.
I like to think of Book Three as Act Three in the three-act story structure model. And Act Three is my favorite part of any novel to write.
You get to have that Dark Night of the Soul moment we talked about at the end of Book Two. You can continue that a bit into Book Three, but really, Book Three is all about the Finale.
Now, if you've read Blake Snyder's SAVE THE CAT, you know he completely glazed over the Finale. What you need is the third book in that trilogy (no lie! There are THREE OF THEM!). It's called SAVE THE CAT STRIKES BACK.
And not only does it have a lot of great info about story structure, but it gives you a five-point finale.
This is exactly what Book Three is. The five-point finale for your series.
Let's examine a little bit here.
1. Gathering the Team: Main characters don't solve problems on their own. They have a team.
In MOCKINGJAY, Katniss have a team of people she's running with as they storm toward President Snow. So your job as the author is to first completely decimate your MC's team, and then gather them up again.
2. Once the team is gathered, they Execute the Plan. They have a plan, and they execute it. There should be an element of "this will never work" to their plan. I like to think of the movie Independence Day when I'm writing this part of my book/series.
Have you seen that movie? The part where Jeff Goldblum and Will Smith are like, "We're going to take this 50-year-old space ship up into outer space, fly into the mother ship, dock with it, download a virus, and fly out of there. Easy peasy lemon squeezy."
I actually scoffed in the theater when I saw it. I was like, "This is crazy! It will never work!"
And guess what? That's the point. It doesn't work.
3. The High Tower Surprise. This is the part of the story where the plan that was being executed in Step 2 goes to pot. Things go wrong, the MC was over optimistic, and hey! The bad guys knew we were coming all along.
It looks like all is lost again, but... is it?!
This is where you have to show that growth in your MC. This is where they take who they were in Book One, combine it with what they learned in Book Two, and create a brand-new person that prevails in Book Three.
Because Act Three (and thus Book Three) is all about synthesis. Word math moment:
Who they were before + What they learned = New person who will overcome
This allows the MC to Dig Down Deep. They're forced to do so because A) there's no back-up plan, B) no one on their team has a solution, and C) they have nothing either. Thus, they have to Dig Down Deep to really strip away everything they thought they knew, and take that leap of faith into the great unknown.
It's when Harry goes into the forest -- alone -- to face Voldemort, and ultimately his death.
Which paves the way for the Execution of the New Plan. And guess what, folks? This one works. It works, because the MC has let go of what they once were. They've searched the deepest parts of themselves, and took a step into the unknown. It works, because the person the MC has become is exactly who was needed all along to overthrow the villain. They weren't that person at the beginning, or the middle, but by the end?
Yeah, they're that person.
And that's what Book Three is about. Synthesizing your MC into the person they need to be to execute the plan that will work.