It is the twilight of the 41st Millennium and the Imperium of Man finds itself besieged by enemies within and without. The daemonic and heretic servants of the Chaos Gods and their mortal champion Abaddon the Despoiler have mustered their full might in preparation for the 13th Black Crusade. Across the galaxy, soldiers of the Imperium muster and prepare to aid in the defense of the fortress world of Cadia against the coming onslaught, but the servants of the Dark Gods are cunning and work to undermine the Imperium form within to pave the way for the imminent Black Crusade. In order to root out and purge this unholy taint, the Imperium turns to the Holy Orders of the Emperor's Inquisition, but with the power of Chaos rising, will the Agents of Throne manage to hunt down these vile heretics or will they fall victim to its insidious power?