Authors sometimes write a book you just can’t do anything with.
It’s broken, and it can’t be fixed.
Essentially, the book can’t be changed because you’ve already got X amount of chapters written and everything’s firmly in place.
Your plot is possibly where it’s broken.
Problems with plot can’t be fixed, and the book has to be discarded.
Problems with TELLING the plot CAN be fixed.
If you realize the plot is broken, it’s extremely difficult to fix it.
How you show or tell the plot can be fixed.
How?
Easy. Shred the chapters that tell the story. Just write new ones.
I know you’ve already got 18,000 words in!
Don’t care.
Fix it.
Even if you have to JUNK those 18,000 words.
Better that than have a novel sitting there you can’t do anything with.