As war rages with the dreaded Obsidian King, Mica Graydier and the disgraced Lord Caleb chase the bearer of a deadly secret across the Windfast Empire. When their quarry slips out of their grasp, they travel to the heart of enemy territory, where Mica must pull off the ultimate impersonation. But there's more going on in the austere foreign kingdom than they realize - and anyone could be a traitor.Can Mica complete her mission before the Obsidian King conquers her homeland? Or will the tyrant use the missing secret to destroy everyone she loves?