Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Straightforward, Innocent
The narrator for The Sign of the Beaver tells it like it is. Nothing's hidden behind complex metaphor and flowery language doesn't decorate developments. Check out this passage to see what we mean:
Matt was feeling well pleased with his day. That morning he had shot a rabbit. He had skinned it carefully, stretching the fur against the cabin wall to dry. Chunks of meat were boiling now in the kettle over the fire, and the good smell came through the door and made his mouth water.
[…]
He could hear the crackle of twigs under heavy boots. Matt leaped to his feet.
"Pa!"
No answer. It wasn't his father, of course. It couldn't be. An Indian? Matt felt a curl of alarm against his backbone. He stood waiting, his muscles tensed. (3.1-4)
The narrator is clued into Matt, and clues us in by sharing Matt's thoughts and feelings in a straightforward way. Matt is never a mystery to us—here we understand the pride he feels about his rabbit and the nervousness he feels about Indians—which grounds us in the story. The straightforward tone sets Matt up as a sort of home base for us as readers to explore the rest of the woods from.
Supporting the narrator's straightforward tone is the fact that Matt's own tone is pretty innocent. He's on his own in the wilderness for the first time, and the newness of everything to him really impacts the story. So when Ben comes alone, for instance, Matt doesn't trust him… but is also confused by this reaction. Check it out:
The man peered curiously over Matt's shoulder through the open door. He could easily see that the cabin was empty.
"You all alone here?"
Matt hesitated. "My father is away just now."
"Be back soon, will he?"
Matt was puzzled by his own unwillingness to answer. He ought to be glad to see anyone after all these days alone, but somehow he wasn't. He didn't quite know why he found himself lying. (3.11-15)
Why doesn't he trust Ben? Because he's a creeper, that's why. But Matt hasn't had a ton of experience with creepers in his life, so he doesn't get it. Good thing he listens to his gut anyway. Matt's innocence crops up time and again throughout the book, and as it does we better understand both his growth and the ways of the world that he finds himself in.