Hiya Jocelyn, I noticed how few people you follow, and wanted to say thanks for picking me to be one of them.
You asked if there was another story to read before Children of the Plague. I wrote the short story "Killing Tiffany Hudson" first, and based Children of the Plague on it. They run concurrently, but are told from different perspectives and in different points of view.
There is a lot that I don't tell in CotP, because it is told mostly from Lanni's perspective, and I only reveal the background info as she remembers/learns about it. The next novel will get more into how it all started and who the major players are behind the scenes.
I hope you enjoy the story(s), and thanks again for reading and following!