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 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.

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.

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.

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.

The Horus Heresy is a civil war on a scale the likes of which the galaxy has never seen before. 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. The Siege of Terra looms, and the fate of the galaxy balances on a razor's edge.

A great darkness has befallen the galaxy, and the armies of Chaos are rampant. To survive, humanity must retaliate and take back what they have lost. By the will of the reborn primarch, Roboute Guilliman, is the Indomitus Crusade launched - a military undertaking that eclipses all others in known history. From the Throneworld of Terra does the Avenging Son hurl his fleets, their mission the very salvation of mankind.

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.

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 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.

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.

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.

When Horus fell, his Sons fell with him. A broken Legion, beset by rivalries and hunted by their erstwhile allies, the former Luna Wolves have scattered across the tortured realm of the Eye of Terror. And of Abaddon, greatest of the Warmaster's followers, nothing has been heard for many years. Until now....

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.