One of the online courses I took about writing cozy mysteries talked about the three stories within a mystery: the story of the crime (how it happened and the backstory), the story of discovery (how the detective figures out what happened), and the prevailing circumstances (the environment in which the story takes place, such as a special event or location). I lump any side-plots, such as the detective's personal problems, into the prevailing circumstances. What I've noticed is that I find some stories, such as the prevailing circumstances, easier to plot (or pants, since I tend to be more of a pantser than a plotter) than the crime story or discovery story. I can actually work out the story of the crime in advance, but plotting the discovery story feels less natural to me. For me, it seems that a lot of the clues my detective has to discover depend on context, which I often don't know until I'm writing it. It's probably due to a combination of me being a pantser and my inexperience with this genre.
Can you think of any other genre that depends on weaving different types of stories together? If so, feel free to discuss it in the comments.