Air — Bobbi Schemerhorn

Khaly and her family must work to solve the ancient riddles before the Sisters destroy the remaining Elementals and force the world to live under their brutal tyranny.

In this final installment of Mechanical Dragons, the Underground's greatest team pursues the Guild's army to prevent the Sisters from instating a reign of pain and slavery.

The Sisters and their Army intend to kill all those that oppose them and eliminate Elementals who will not submit, but first they need one last piece to solve an ancient puzzle. They must never find it.

Tired and frustrated the war has taken its toll on Khaly's family. Armed with the journals and scribblings from the monuments, they must unravel the legends to discover what the Sisters already know. Beating the enemy to the treasure is the group's only hope of success.

Khaly must work to keep her family together, amidst the bickering and squabbles brought out by the strain of war. Their individual skills are necessary to complete the difficult tasks ahead. If Khaly and the others fail, their world is forfeit, along with their lives.