After being captured by the Inquisition, the Venatori mage Cassius Terro was given a simple sentence: Return home. An upstart Praeteri adopted into a fading Altus family, Cassius had already risen high for his low birth. But with the Imperium divided into factions after the rise of the Elder One, he finds tangled in a precarious web - bound by his loyalties, duties and promises.

The Templar Order has fallen and the faith that had once bound Cain Wygard to it has run out. The Breach and the request of an old friend drew him to the Inquisition. The emergence of the Red Templars gave him new resolve. But not all of the Order has been twisted, an unknown force is drawing both the corrupted and the pure to the west as red lyrium spreads across the world.