Independence (Two Democracies Book 0) by Alasdair Shaw is a short story, very short really. It masterfully sets up the events in the upcoming Two Democracies series and introduces the two main characters, and one of them isn't human as far as I can tell.
So why are these two democracies at war? That remains one of the top questions in my mind and I certainly hope it will be answered when book 1 comes out. (it said to be soon!)