The War of Undoing by Alex Perry

The War of Undoing is, at first appearances, a pretty straightforward book. The humans and the vuma live in an uneasy (and clearly temporary) peace. [ominous thunder]

With that established, cut to...

Three children - the Rainings - living alone, unchaperoned, and in poverty in the unwelcoming city of Tarot. They receive a mysterious message saying that they're needed for a Great and Magical Cause. This gift horse seems like a truly spectacular chance. They can leave the city, pursue their cap...