The Inside Story (Sisters Grimm #8‪)‬

The fate of all fairy tales is at stake in the eighth adventure in the beloved New York Times bestselling Sisters Grimm series
 
Sabrina and Daphne Grimm have studied hundreds of stories as part of their training as fairy-tale detectives, but they never thought they’d actually be in one. And yet that’s exactly what happens when they follow the diabolical Master into the Book of Everafter, a mysterious tome in which copies of the world’s fairy-tale characters live out their stories over and over again. The Grimms must track down the Master while avoiding the Book’s tyrannical Editor—who is devoted to keeping the stories on track—and his army of story-gobbling revisers. In the Book of Everafter, stories can be rewritten and destinies changed, which is why Sabrina and Daphne must find the Master before he can alter his own fate—and the fate of the whole world.