Forged in Blood II (Emperor's Edge Series #7) by Lindsay Buroker

Amaranthe Lokdon survives her reckless plan to destroy the enemy's weapon-filled super aircraft only to learn that thousands of people perished when it crash landed. Half of her team is missing... or dead. Meanwhile, the fighting in the capital has escalated, the Imperial Barracks have been taken by a pretender, and a deadly new danger threatens the populace. Amaranthe's hopes of returning Emperor Sespian to the throne and bringing peace to the empire are dwindling by the hour.

To make matters worse, her strongest ally-and closest friend-has been captured and is under a powerful wizard's control. If she can't figure out a way to free Sicarius, he may kill them all when next they meet...