Did the AI “fail,” or did you use AI in a suboptimal way?
If you had started the conversation by feeding in the actual text of the book, you would have very different results, because you would be grounding on context rather than asking the model to “figure it out somehow” based on training data.
Not sure what you were expecting, using AI is mostly about context management, and if you don’t set up the context correctly you’re asking for results similar to this.