Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Sassy, Defiant, and Preachy
Witch and Wizard is set in a bleak world with an oppressive government. Fortunately, Whit and Wisty provide some comic relief by giving government officials like the Matron and the Judge a lot of lip. For instance, instead of cowering from the Visitor, Wisty is a smart-aleck: "Let me guess. No one loved you as a child. Or as an adult. Well, tough noogies!" (26.3). Ha. These kids are not going to sit back and accept their fates; instead, they push back whenever possible. And through their defiance, we see that the appropriate response to a world gone mad is to resist.
In the final chapter, Wisty breaks from describing the action to address the reader directly:
So how are you doing—whoever you are? Listen, please: seize the moment, however worried you may be about what's coming next. It's your brain, it's your life, it's your attitude…. Go out there and fill up with sights, sounds, and ideas that are bigger than yourself. We all know from history—to say nothing of this current reality—what can happen if we stay quiet and just do what's put in front of us. (104.12)
It's a very explicit statement of the book's message, which is been hammered home throughout the rest of the book. So in addition to bringing the sass and defiance, this book's tone also gets a little preachy.