by Jim Butcher
Book 4 in the Codex Alera series (2007)
In his acclaimed Codex Alera novels, bestselling author Jim Butcher has created a fascinating world in which the powerful forces of nature take physical form.
For millennia, the people of Alera have used their unique bond with these elementals for protection. Now, as enemies become allies, and friends become bitter foes, a danger beyond reckoning looms. . . .
After two years of bitter conflict with the hordes of invading Canim, Tavi of Calderon, now Captain of the First Aleran Legion, realizes that a peril far greater than the Canim exists-the mysterious threat that drove the savage Canim to flee their homeland.
Now, Tavi must find a way to overcome the centuries-old animosities between Aleran and Cane if an alliance is to be forged against their mutual enemy. And he must lead his legion in defiance of the law, against friend and foe–or no one will have a chance of survival . . .