One of my favorite things to see is when an author pulls in so many small details from previous books that end up being big. In book 1 of the naturals, you have her encounter a man that would come into play later (nightshade). When you originally wrote it,

Great question! When I sold The Naturals, I sold it in a two-book deal, so although I had some vague ideas for later books and planted a few things I could harken back to if I got to write more, I wasn’t counting on for sure getting to write Books 3 and 4. So for Book 1, Nightshade was meant as a red herring, but even as I wrote it I thought “Who is this guy and why is he so interested in these kids?” and made a mental note to figure that out as the series went along. 

Long story short: I didn...