After a long and gruelling conflict, the traitors at last close upon Terra. But time is dwindling for an attack. Both Guilliman and the Lion are returning with all haste, and their armies could turn the tide. The hosts of the Warmaster must unite, for only then can they attack the Throneworld itself. While Mortarion is sent on ahead as the fleet’s vanguard, it falls to Lorgar and Perturabo to marshal Fulgrim and Angron, both now elevated to daemonhood and perhaps beyond even the will of the Warmaster to command.

Imperium Secundus lies revealed as a heretical folly. Terra has not fallen, though it remains inaccessible. Sanguinius, Guilliman and the Lion El’Johnson, the primarchs of the Triumvirate, must reach Terra at all costs. They seek to defend the Emperor and to atone for their sins. But the Ruinstorm, a galaxy-wide maelstrom of chaos, hides the Throneworld from the primarchs. Now the fleets of three Legions depart Macragge, and the primarchs will stop at nothing to overcome the Ruinstorm.

Reborn in body and spirit beneath Mount Deathfire, the primarch Vulkan gathers his most trusted sons and prepares for the final part of his journey. The Legions shattered at Isstvan V have stalled the Warmaster’s advance across the galaxy, but fresh cracks are spreading through the alliance between the Iron Hands, Salamanders and Raven Guard, along with mysterious rumours of the return of Ferrus Manus. Haunted by a sense of destiny unfulfilled, Vulkan must choose between joining their war of vengeance against the traitors and following his own barely understood path all the way to the Throneworld itself.

As the darkness of the war slowly consumes the galaxy, those who still serve the Throne are faced with a struggle for their survival and the continued existence of everything they hold dear. With the threat of the Warmaster's fleet looming ever closer to Terra, it will fall to such heroes to halt the tide, but the enemies arrayed against them are powerful, and the burden of loyalty is great....

Born of the fiery world of Nocturne, the Salamanders believe in self-sacrifice and the sanctity of human life. Their father, Vulkan, was raised on this world, a blacksmith's son from humble origins who became a primarch of the Emperor of Mankind and forged his sons into a Legion. Their saga is one of heroism, betrayal, tragedy and rebirth. They have returned from the edge of extinction more than once, forever embattled, never bowed, the Legion and their primarch the epitome of defiance in the face of adversity. Unto the anvil, born of flame. 

The Traitor Host of Horus Lupercal tightens its iron grip on the Palace of Terra, and one by one the walls and bastions begin to crumple and collapse. Rogal Dorn, Praetorian of Terra, redoubles his efforts to keep the relentless enemy at bay, but his forces are vastly outnumbered and hopelessly outgunned. Dorn simply cannot defend everything. Any chance of survival now requires sacrifice, but what battles dare he lose so that others can be won? Is there one tactical stroke, one crucial combat, that could turn the tide forever and win the war outright? 

Each primarch is an exemplary being, derived from the Emperor’s own genetic stock to embody a facet of His personality. Their powers are unfathomable, but only one of them is the First. Lion El’Jonson is the paragon of what it is to be a primarch. His Legion, pre-eminent for most of their long history, typify the virtues of temperance, pride and martial excellency that the Lion embodies. They are the Emperor’s last line and final sanction. They are His Dark Angels. 

For long years, the Horus Heresy has ground on. Now, the Death Guard have been sent to begin the final battle. But Mortarion and his sons must face their gravest challenge first - for Nurgle has claimed them as his own, and he will not be denied.... The skies darken over Terra as the final battle for the Throne looms ever closer.... As the Traitor primarchs muster to the Warmaster’s banner, it is Mortarion who is sent ahead as the vanguard of the Traitor forces. But as he and his warriors make way, they become lost in the warp and stricken by a terrible plague. 

A galaxy burns and brother turns on brother as the conflict brought about by a beloved son’s betrayal reaches its fateful end. The Warmaster Horus has triumphed. His massive fleet at last nears Terra and the patriarchal Throne of his hated father. Many have fallen to bring this moment about; their tales are the ashes upon which the Heresy was born and prospered. Others have played their own small parts, drops in an ocean of war and blood. None of it matters. Terra looks to the skies as it raises its defences. Armies muster, heroes raise their swords, citizens cower. The war is coming. And nothing can stop it.

Removed from the concerns of the galaxy at large and regarding the Warmaster's unfolding Heresy with cold detachment, he has dedicated his hollow existence to the preservation of all the knowledge once held in the great libraries of Tizca, should mankind ever seek such enlightenment again. But his sons can see the change in their primarch - he is a broken soul whose mind and memories are slipping away into the tumult of the warp.

While Horus' rebellion burns across the galaxy, a very different kind of war rages beneath the Imperial Palace. The 'Ten Thousand' Custodian Guard, along with the Sisters of Silence and the Mechanicum forces of Fabricator General Kane, fight to control the nexus points of the ancient eldar webway that lie closest to Terra, infested by daemonic entities after Magnus the Red's intrusion.

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. 

From out of the shadows of the Silent War, a hero emerges. Clad all in grey, an errant warrior of the Legiones Astartes kneels before the Regent of Terra, and accepts a solemn new duty - Battle-Captain Garro, once commander of the Eisenstein, now Agentia Primus of Malcador the Sigillite. From the desolation of Isstvan to the halls of the Imperial Palace itself, he stands as a paragon of loyalty and protector of the innocent, ever ready to strike back at the traitorous allies of the Warmaster.

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.

As the Warmaster's campaign of galactic domination continues, his generals seek out fresh battlefields to conquer. After leaving the Crone World of Iydris behind, Perturabo strikes for Tallarn. A bitter, vengeful primarch, the lord of the Iron Warriors unleashes a deadly bombardment against the world, killing millions but entrenching the survivors. A brutal, all-consuming armoured conflict ensues, the greatest of the war and one that grinds down all combatants over more than a year of relentless battles.