If you simplify this book, it is about two healers working to save people from a plague and a new mysterious disease. 

But, really, this story is about so many things - identity, family, political history, immigration, etc.

I was pulled in at the beginning, but the story lost me a bit in the middle due to pacing issues. There wasn't really a lot happening. The ending was much stronger. 

Overall, a very interesting story concept. I believe the author said this is a standalone, but is introducing this specific world. I would be interested to read more.