I always find that those middle chapters of any book are something of a slog. Early on, with my first several books, I'd have a crisis somewhere between halfway and two-thirds of the way through. I'd suddenly decide that there was no story there, no book to write, no series worth reading, no hope of a career. Then I'd figure it out and by the time I was 80% done I'd be telling my wife how much I liked the book. Drove her nuts. I still hit mild doldrums in the middle of each project, but I seem to have moved past the crisis thing. Here's hoping you're past the doldrums on this project. I hope the rest of it goes well.