Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Gravely serious; relieved and hopeful without being jubilant
Silko's description of Tayo's love affair with Ts'eh is a perfect example of the tone of the novel:
Their days together had a gravity emanating from the mesas and arroyos. (XXV.116)
OK, that's a beautiful sentence, but come on—this is a love affair we're talking about. Most novels would show Tayo skipping about with giddy excitement. Not in Ceremony. Here he cries because Ts'eh loves him so much. Kind of emo, if you ask us.
Needless to say, this isn't what you would call a lighthearted novel. The gravity of Silko's tone lets us know that the story she has in store for us is of serious importance. We're not just talking about the life of one sick veteran here. The fate of the entire world is at stake. No pressure or anything. Even when things work out for our protagonist in the end, no one's jumping for joy. The tone is more relieved than jubilant—after all, Tayo just barely makes it. And though he has been healed, several of his friends have lost their lives in the process.