The Inside Story (Sisters Grimm #8) by Michael Buckley
First, a Rant:
I don't remember everything about this book, but I seem to recall that it is not my favorite in the series.
However, based on the ending of "The Everafter War," I have to rant a little. So, the Everafters are real people and the tales told about them are actual historical events. Except to the extent that they aren't. Because the lives of the Everafters can be changed by going into a book and changing the events of the book. So they're not real people after all. They're sort of incursions of fictional characters into our reality, or something like that.
I also take issue with the idea that every version of their stories could possibly be in the Book of Everafter. Not on a pagecount basis or anything like that, but because then wouldn't there have to be as many versions of, say Little Red Riding Hood as there are versions of the story? There would have to be the Perrault version as well as the Grimm version. Also, among others, presumably, the version from "Into the Woods" would be in there, as would Thurber's "The Little Girl and the Wolf," and the movie "Hoodwinked!" So if you wanted to use the Book of Everafter to change the story, wouldn't you have to be very careful to make sure you were in the right one? Because it wouldn't do any good to change the history of Perrault's Little Red Riding Hood if the one you are concerned with is the Grimm version. And wouldn't that lead there to be several versions of Red and the Wolf running around town? As an aside, I certainly wouldn't go into the Book of Everafter to change the Thurber version. I like the Thurber version just fine the way it is, by the way, and if you haven't read it, I recommend you check it out.
Now for The Story:
We now know that the Mirror, Granny Relda, Daphne, and Sabrina's friend, is The Master. He intends to make his way through the Book of Everafter to Snow White, where he will then get Bunny Lancaster to give him the ability to take over the body of Daphne and Sabrina's little brother. This will make him human and thus able to cross the barrier that separates Ferryport Landing from the rest of the world.
It turns out that, for reasons that we will see in the final book in the series, The Council of Mirrors, trying to get into and change Snow's story is not a good idea.
Daphne, Sabrina, and Puck follow Mirror through a lot of stories, including but not limited to Pinocchio, the Legend of Sleepy Hollow, and the Wizard of Oz. Since they have a goal beyond reliving the story, they make changes to the story, leading to the intervention of the Editor and his Revisers (just wait 'til you meet them!).
The book ends on two unrelated cliffhangers that lead into the next (and final) book in the series, The Council of Mirrors.