The Space Marine Legions of the 31st Millenium field a diverse and formidable range of genetically-enhanced warriors and advanced war machines, superior to any other military force in the galaxy. As an Age of Darkness falls across the stars and the fires of rebellion rage out of control, the armies that were used to forge the Imperium turn upon each other in an apocalyptic civil war – the Horus Heresy.
Haarken Worldclaimer, Herald of the Apocalypse, leads one of the mightiest traitor hosts every assembled. His mission, ordained by Abaddon the Despoiler himself, is to smash aside all Imperial resistance and claim the Nachmund Gauntlet in its entirety. This lawless place is home to pirates, xenos, traitors and renegades – yet Nachmund is strategically vital to the Imperium of Man, for it remains the most stable route known through the Great Rift. Should it fall, contact between Terra and the Imperium Nihilus would be all but lost.
As vast and dark as a sunless void, the Blackstone Fortress is a creation far beyond the ken of any race in the galaxy. In this age of darkness, in a galaxy riven with strife and horror, the desperate and intrepid alike search this Fortress for long-lost technologies that may be used to turn the tide of war.