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 Indomitus Crusade has brought the Emperor's vengeance to thousands of star systems. The fleets and armies under the leadership of Roboute Guilliman fight for the survival of humanity against the forces of the Chaos Gods. But the traitors and heretics are not the only foe looking to destroy the rule of Terra. Xenos prey on human worlds in numbers not seen for millennia. Worst amongst them are the rampaging orks, whose migration conquests threaten to reverse the many gains of Fleet Primus. 

The Indomitus Crusade continues its war across the stars. The primarch Roboute Guilliman has finally broken through the orkish threat bedevilling the sectors near Fenris, and makes ready to push on his bid to stabilise the Imperium Sanctus—but old and bitter foes stand in his way. Kor Phaeron, the Dark Cardinal, threatens the previously stable core of the Segmentum Solar. Waves of rebellion instigated by his infiltrating priests suggest an imminent, large-scale invasion by the Word Bearers Legion. 

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. 

As Guilliman, Regent of Terra, heads off to lead the Indomitus Crusade, he leaves behind a world still in turmoil, beset by cult activity. Stripped of its huge armies for the galactic offensive, recovery is precarious. The Custodians do what they can while keeping the Palace secure, and the Sisters of Silence rebuild their citadel on Luna. When the warship Phalanx returns, it seems that stability will at last be assured. However, as reconquest forces push out further into the slums, they come across signs that another mysterious foe is active.

The Throneworld is in turmoil, wracked by the opening of the Great Rift and the failure of the Astronomican. Inquisitor Erasmus Crowl, his mind and body ravaged by what he has seen in the Hollow Mountain, is missing, taking with him the clues to the conspiracy that has come to obsess him. Luce Spinoza, his interrogator, must choose whether to seek him out or defend her diminished realm from the many forces that still seek to destroy it. As enemies circle, Interrogator Spinoza enters a race against time to find the evidence she needs.

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. 

The Custodian Guard have stood watch over the Emperor's Palace on Terra since the foundation of the Imperium. Charged with protecting the Master of Mankind from all threats, within and without, their fearsome resolve is renowned throughout the galaxy, and their golden armour is the last thing that a would-be assassin or saboteur will ever see.

In the hellish sprawl of Imperial Terra, Ordo Hereticus Inquisitor Erasmus Crowl serves as a stalwart protector, for even the Throneworld is not immune to the predations of its enemies. In the course of his duty, Crowl becomes embroiled in a dark conspiracy, one that leads all the way to the halls of the Imperial Palace. As he plunges deeper into the shadowy underbelly of the many palace districts, his investigation attracts the attention of hidden forces, and soon he and his acolyte Spinoza are being hunted.

The primarch Roboute Guilliman of the Ultramarines has returned in the galaxy’s hour of need, and all muster to his Indomitus Crusade to hold back the darkness. Amongst these heroes is Cato Sicarius, Master of the Watch and vaunted captain of Second Company. Disaster befalls Sicarius and his brave warriors as their ship, the Emperor’s Will, is lost to the hellish warp, its entire crew believed slain. But Sicarius endures, though he and his men are fighting for their very survival against the denizens of the Great Rift - the daemons and renegades of Chaos.  

The galaxy is in flames. Chaos is in the ascendant across the stars. The Great Rift has split the holdings of the Imperium in twain, isolating entire sectors from the light of Holy Terra. But all hope is not lost. The Primarch Roboute Guilliman has returned from deathless sleep and appointed Commander Dante, lord of the Blood Angels, as Regent and Warden of the newly dubbed Imperium Nihilus. In the Baal system, the shattered holding of the Chapter is being rebuilt, and Dante plans the greatest campaign of his long life, to retake half an empire. 

Throughout the tortured galaxy, Ephrael Stern is known by many names. The Thrice-born. The Daemonifuge. The Heretic Saint. Trapped deep within Imperium Nihilus following the coming of the Great Rift, the maligned Sister of Battle fears the Imperium is no more. The God-Emperor’s light, which has guided her through centuries of strife, has too extinguished. Seemingly forsaken, Stern is bereft until a mysterious stranger arrives, offering her a new destiny. One that might yet see the Imperium saved. Stern must prove herself worthy of the God-Emperor’s grace once more. 

The Officio Assassinorum safeguards the future of humanity. Its agents are the bloody-handed, secret saviours of the Imperium, killers charged with achieving the impossible...and Vindicare assassin Absolom Raithe has just been handed the most difficult assignment of his career.

When the vital forge world of Orestes comes under attack by a legion of Chaos Titans, the planet is forced to appeal for help. The Titans of Legio Invicta, although fresh from combat and in desperate need of refit and repair, respond, committing their own force of war engines to the battle. As the god-machines stride to war, the world trembles, for the devastation they unleash could destroy the very world they have pledged to save.

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?