After a series of victories, the Imperial forces are on the back foot once more. The power of Chaos is rising, the Traitors gain ground, and all hope seems lost. Can Terra endure? 

The paths of Roboute Guilliman and his fallen brother Mortarion bring them inexorably together on Iax. Once a jewel of the Imperium, the garden world is dying as the plans of the Lord of Death to use it as a fulcrum to drag the stellar realm of Ultramar into the warp come to deadly fruition. While Guilliman attempts to prevent the destruction of his kingdom, Mortarion schemes to bring his brother low with the Godblight, a disease created in the Cauldron of Nurgle itself, made with the power to destroy a son of the Emperor. 

Legends abound of the glorious - or infamous - deeds of the emperor's sons. Yet almost nothing is known of Alpharius, the most mysterious of them all, for the lord of the Alpha Legion is unparalleled in the art of obfuscation. Such are his gifts of secrecy and deceit that even his rediscovery has remained an enigma - until now. But when the tale comes from the serpent’s mouth, where do the lies end and the truth begin?

Kept alive and imprisoned for 10 thousand years, Luther is the curse and the salvation of the Dark Angels made manifest. None are so close to the heart and history of the Chapter as the man that embodies all that was great about the First Legion and all that is shameful about the Dark Angels. In his story is writ the tale of the Horus Heresy and the fall from Enlightenment in a single long life. Glory, honour, pride, shame and betrayal weave a tapestry of truth and lies that the Supreme Grand Masters of the Dark Angels have sought to understand and unbind across 10 bloody millennia. 

Fell times have come to the galaxy. Cadia has fallen, destroyed by the onslaught of Chaos. A Great Rift in the warp has opened, and from its depths spew daemons and the horrors of Old Night. But all hope is not lost… A hero, long absent, has returned, and with him comes the wrath of the Ultramarines reborn. Roboute Guilliman has arisen to lead the Imperium out of darkness on a crusade the likes of which has not been seen since the fabled days of the Emperor. But never before have the forces of Ruin amassed in such numbers, and nowhere is safe from despoliation. 

In the void and upon the worlds of Greater Ultramar, the battle for the Imperium continues. Intent on rebuilding his home realm and using it as a base to reconstruct the ravaged stellar empire of mankind, the returned primarch, Roboute Guilliman, proceeds with his war to drive Mortarion and his Death Guard Traitor Legion from the domain of the Ultramarines. But when Guilliman brings his brother to battle upon the diseased plains of Parmenio, the intervention of a greater power in their fraternal struggle threatens to upend the Imperial Regent’s understanding of the galaxy. 

As the Indomitus Crusade begins, fleets of mighty warships leave Terra on a vital quest to stabilise Imperium Sanctus in the wake of the Great Rift. The returned primarch, Roboute Guilliman, leads a huge force towards the shrine world of Gathalamor, where stable warp routes will allow the flotilla to spread across the beleaguered southern half of the Imperium.

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? 

In the city of Queen Mab, nothing is quite as it seems. Pariah, spy and Inquisitorial agent Alizebeth Bequin is all of these things and yet none of them. An enigma, even to herself, she is caught between Inquisitors Gregor Eisenhorn and Gideon Ravenor, former allies now enemies who are playing a shadow game against a mysterious and deadly foe. Coveted by the archenemy, pursued by the Inquisition, Bequin becomes embroiled in a dark plot of which she knows not her role or purpose.

On the battlefields of Aexe Cardinal, the stalwart forces of the Imperial Guard are locked in a deadly stalemate with the dark armies of Chaos. Colonel-Commissar Ibram Gaunt and his regiment, the Tanith First and Only, are thrown headlong into the living hell of trench warfare, where death by an unseen enemy is always just a moment away. The only chance for Gaunt and his lightly armed scouts to survive is to volunteer for a mission so dangerous that no one else dares accept it.

In the darkness beyond the galaxy, there are monsters. Some swim closer to the light, drawn by the beacon that is the Astronomican, while others stalk the Void, predators in the dark. The Carcharodons have hunted for millennia, but now they are drawn into a new blackness...the Dark City of the drukhari itself. Commorragh. For a thousand years, Chaplain Tangata Manu has searched for a relic lost under his watch: an ancient thing, once charged into the keeping of the Forgotten One himself. But at the brink of seeing his hunt fulfilled and the relic returned, it is stolen from under him.

The war for the fate of mankind blazes on. Though the outer defences have fallen, the walls of the Palace itself remain inviolate as Rogal Dorn, the Praetorian of Terra himself, uses every known stratagem and ploy to keep Horus' vast armies at bay. In Perturabo, the Traitor siegebreaker, Dorn faces an adversary worthy of his skill. A terrible, grinding attrition ensues. The crucial battle for the Lion's Gate spaceport is at the heart of this conflict. With it in their possession, the Traitors can land their most devastating weapons on Terran soil. Dorn knows it must not fall.

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. 

Cadia, 10,000 years a stalwart bastion against Chaos, is broken. Its collapse at the hands of Abaddon and the Thirteenth Black Crusade has fractured the Imperium of Man, and in its wake spreads the seeds of heresy, lies and insurrection. It falls to Cadia’s survivors to fight on, bloodied but unyielding, in the name of the Emperor. On the world of Malouri, traitorous forces have retreated to the impregnable island fortress of Crannog Mons.

Ahriman, greatest sorcerer of the Thousand Sons and architect of the Rubric that laid his Legion low, continues to walk the path towards salvation, or damnation. Searching for a cure for his Legion, he is forced to consider - was the great ritual somehow flawed from the very beginning? The answer may lie within the mysterious artefact known as the Athenaeum of Kalimakus, a grimoire of forgotten knowledge that is reputed to contain the exact words of the lost Book of Magnus...or, perhaps, even a transcription of the primarch’s deepest and most secret thoughts.