Ok, roughly 20% into the book (I'm listening while working on some admin tasks), there is no plot in this book so far.
So far, Fforde has basically just recapped what happened in the first two books.
If I were reading this one right after book # 2 (to continue with the series), I'd be pretty peeved with the lack of plot. The book just feels like a filler.
For my purposes, it kinda works as I don't have to expend a lot mental effort on it, but I am glad I managed to get the audiobook from my library's online service.