Here's a bit about it:
Wren is human. Isaac is not. Having switched places at birth, they now live with each other’s families. Growing up among a different species is difficult—for Isaac, who has to keep many secrets, and for Wren, who is teased for her lousy human senses. They’re told it’s necessary, though. The exchange is the first step in an ambassador program meant to ensure peace.
But not everyone wants peace. There are creatures that live deep underground, coming up to the surface to feed. They have a plan to stir up trouble, and so far, it’s working. In the end, it’s up to Wren and Isaac to prevent a looming war and to save both their kinds.