After seven long years of conflict, the Horus Heresy nears its end. But now, as the Warmaster Horus marches on Terra to rip his father from the Throne, the seat of the arch-traitor’s power lies empty. Cthonia, a world once dominated by brutal murder-gangs, is occupied by the Emperor’s praetorians—the indomitable Imperial Fists. For the Sons of Horus, this outrage demands a reckoning.

Horus has rebelled against the Emperor by purging his and his brother's Legions, but what was supposed to be a secret act of murder has been revealed. In the Emperor's name, Rogal Dorn and Malcador the Sigillite dispatch the largest force of legionaries and primarchs ever assembled to end Horus' rebellion before it can begin. But the loyalists, on their way to enact vengeance, do not know the depth of the betrayal they face. They will not be the perpetrators of a massacre, but its victims.

After seven years of bitter war, the end has come at last for the conflict known infamously as the Horus Heresy. Terra now lies within the Warmaster’s sights, the Throneworld and the seat of his father’s rule. Horus’ desire is nothing less than the death of the Emperor of Mankind and the utter subjugation of the Imperium. He has become the ascendant vessel of Chaos and amassed a terrible army with which to enact his will and vengeance. But the way to the Throne will be hard as the primarch Rogal Dorn, the Praetorian and protector of Terra, marshals the defences.

This Horus Heresy anthology contains eighteen short stories by authors such as Graham McNeill, Aaron Dembski-Bowden, Nick Kyme, and many more. Also, Chris Wraight’s acclaimed novella Brotherhood of the Storm delves into the nature of the elusive White Scars Legion, and their questionable sense of duty to the Emperor.

On the 13th day of Secundus, the bombardment of Terra began. With the solar defences overcome through the devastating strength of the Traitor armada and the power of the warp, Horus launches his assault on the Throneworld in earnest. After withstanding a ferocious barrage of ordnance, an immense ground war commences outside the Palace, with every inch gained paid for in the lives of billions.