It is the 32nd millennium, and the Imperium is at peace. The Traitor Legions of Chaos are but a distant memory, and the many alien races that have long plagued mankind are held in check by the Space Marines. When a mission to exterminate one such xenos breed on the world of Ardamantua draws in more of their forces, the Imperial Fists abandon the walls of Terra for the first time in more than a thousand years.

For a thousand years, the Sabbat Worlds have been lost to the Imperium, claimed by the dread powers of Chaos. Now, a mighty crusade seeks to return the sector to Imperial rule. And at the forefront of that crusade are Colonel-Commissar Ibram Gaunt and the Tanith First and Only - better known as Gaunt’s Ghosts. Trapped in the grinding trench warfare of Fortis Binary, the Ghosts find themselves drawn into a conspiracy to assassinate the crusade’s leader, Warmaster Macaroth.

The primarchs, nigh-immortal sons of the Emperor of Mankind, take the stage in a series of short stories showcasing some of their great deeds and hideous acts from across the Great Crusade and the Horus Heresy.

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.

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.

Under almost constant besiegement by the hosts pouring from the Eye of Terror, Cadia acts as a bulwark against tyranny and death. Its fortresses and armies have held back the hordes of Chaos for centuries, but that grim defiance is about to reach its end. As Abaddon's Thirteenth Black Crusade batters Cadia's defences, and armies of the Imperium flock to reinforce this crucial world, a terrible ritual long in the making comes to fruition and the delicate balance of this brutal war shifts.

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.

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.

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.

Legend tells of a foolhardy expedition, led by the radical Magos Telok, that ventured out into the unknown space beyond the Halo Worlds in search of the 'Breath of the Gods' - an arcane device with the power to unmake and reshape the very stars themselves. Thousands of years later, the ambitious Lexell Kotov musters his Adeptus Mechanicus Explorator fleet and sets out to follow in mad old Telok's footsteps.