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 age of the Dark Imperium, Primarch Guilliman’s Primaris Ultramarines are a shining beacon in the darkness of war. On the Imperial Hive World of Ikara IX, Chaplain Kastor and Apothecary Polixis, brothers in blood as well as in battle, stand firm against the endless Greenskin horde. But a threat is looming. An invasion like no other assaults the broken city of Shebat, as the crazed warlord Urgork arrives to lay waste to the Imperial forces and capture a Primaris Marine for his own twisted ends.

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.

Newly promoted to the captaincy of the Ultramarines Fourth Company, Uriel Ventris leads his warriors to the world of Pavonis, where vicious alien raiders are bringing death and destruction. As Pavonis descends into political turmoil, Uriel and his warriors must battle the xenos as they unravel a plot to unleash an ancient evil buried deep beneath the world - the mysterious and deadly Nightbringer.

The shrine world of Divinatus Prime has become lost to the light of the Astronomican, and no ship can piece its veil. Only the Lord of Death himself, Blood Angels Chief Librarian Mephiston, has any hope of discerning the fate of this once pious world. After enacting a powerful blood ritual, Mephiston and an honour guard of his fellow Blood Angels reach the stricken shrine world to find it seized by religious civil war. Each faction fights for dominance of a potent artefact, the Blade Petrific, said to be wrought by the Emperor Himself.

After the Great Crusade united the disparate worlds of humanity, the very warriors who made it possible turned on each other and tore it apart. This war was not only fought on a galactic scale – it was contested a million times over in brutal battles between former brothers and allies. Since the near-destruction of the Iron Hands, Raven Guard, and Salamanders on Isstvan V, scattered warbands from these 'Shattered Legions' have waged a guerrilla war on Horus' forces across the galaxy.

He is known by many names - Clonelord, Manflayer, Primogenitor. He is the epitome of deceit and perversion, and feared by man and monster alike. Once the Chief Apothecary of the Emperor's Children, the madman known as Fabius Bile possesses a knowledge of genetic manipulation second to none.

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 Blood Angels Chapter of Space Marines is under threat. Having obliterated all human life in the Red Scar region of space, the largest tendril of Hivefleet Leviathan ever seen in the Imperium has converged and is making relentlessly for Baal. To face this awesome foe, Commander Dante has called upon the Successor Chapters of the ancient Ninth Legion. The Sons of Sanguinius gather in numbers not seen since the dark days of the Horus Heresy.

The eldar are an ancient race whose mode of war blends spirituality with a unique mastery of technology. In times of need, their entire race will rouse to war, led by terrifying, almost mythological figures - the phoenix lords, immortal beings that embody the warrior nature of the eldar. When a burgeoning ork empire starts to pose a threat to the eldar peoples, Jain Zar travels to the craftworld Ulthwé to warn them of the danger.

The Aeronautica Imperialis are the masters of the skies in the 41st millennium, waging wars of breakneck aerial combat where only skill stands between victory and death. Flight Commander Lucille von Shard is an ace, a living exemplar of what it means to fly in the name of the Emperor… or so Propagandist Kile Simlex is told. Braving the foetid waters of Bacchus and its rampaging greenskin hordes, Simlex is tasked with producing a cinema-pict portraying Shard as an Imperial hero. Shortly after his arrival planetside, however, he discovers the war effort is in shambles.

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.

For nearly 10 millennia, the Crimson Fists waged war against the enemies of mankind from their home planet of Rynn's World. And then, in one cataclysmic event, Rynn's World fell, despoiled by the hordes of the orks. Six months later, Chapter Master Pedro Kantor leads the shattered remnants of his Space Marines in pursuit of a force of greenskins still clinging to life in the mountains of the devastated world.

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.

Horus is dead. Terra lies in ruins. Amid the rubble of the Palace, shell-shocked survivors emerge into the light of an uncertain dawn. New powers are present now, ones that have travelled the length of the galaxy to bring salvation to the Imperium, though they are as readily cast as usurpers as redeemers. The survivors of the Traitors’ Grand Armada, now scattered and desperate to escape vengeance, are riven with doubt and dissension, and their gods too are silent. Amid all the grief and confusion, some hopeful souls believe the war to be over and an era of renewal just ahead.