Clockwork Secrets: Heavy Fire (Clockwork Heart, #3)

The conclusion of the Clockwork Trilogy, in which Taya and Cristof are sent to Alzana to return the captive airship crews and negotiate for peace with King Quintilio. As international tensions escalate, war is declared on Ondinium, striking at its massive metal heart and resulting in the undoing of Ondinium s isolationist policies as it accustoms itself to a world where it no longer holds military superiority."