Kingslayer and battle-mage Taki Natalis now fights for the empire that conquered his homeland. It's not a question of loyalty: it's a choice between kill or be killed. Battered by defeats on the Ursalan campaign, Taki and his squadmates must race against time to find a legendary, ancient fortress suspended in the heavens. But their nemesis, the Sanctissimus Rex, desires it too and will stop at nothing to harness the unimaginable power waiting within. Mighty foes, unhinged commanders, and malevolent fortune stand in the way, but the lives of millions hang in the balance.