Poirot and Ms Marple fascinated me in their seemingly quirky ability to ferret out the many truths of a situation - the story is never just about "who done it" - though of course they each had a method, coupled with discipline and discernment.
Method, discipline and discernment.
In many ways these words also describe the research process. No surprise, really. The art of detection, be it in a fictional character or the real world, is a process of research, figuring out what is possible within the context of any given problem. To quote Holmes himself:
How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth?
Just a perusal of the Wikipedia page of Sherlock Holmes quotes demonstrates this recurring theme across many stories.
I personally find this mystery/puzzle motif a powerful motivation for learning, and I've used it for years when sharing my knowledge of business research tools and techniques (presentation at CLA 2010 here). By imagining the process through this lens I think it demystifies unfamiliar content by placing it in a familiar framework that combines 1) fun and games on the one hand, and 2) existing skill sets on the other.
So much of research and reference is figuring it out as we go - Librarians don't know all the answers, but we have a method, coupled with discipline and discernment, to know how to look for the answers. It is about the unique relationship between what is known and what is needed, and creating that improbable bridge that links them.