The profound, galaxy-shaking events of the Gathering Storm have irrevocably changed the very nature of the Warhammer 40,000 universe.
The world of Cadia, the long-standing symbol of Imperial defiance against the encroaching tides of Chaos, finally fell to the full fury of Abaddon’s Thirteenth Black Crusade. Craftworld Biel-Tan, home to the most militant of the Eldar craftworlders, was shattered, and along with it their dreams of restoring their diminished race to prominence. Throughout it all, Chaos is in the ascendant, with Warp storms causing havoc across the galaxy as reality loses ground to the Immaterium.
And yet, there is now also hope. The culmination of an ancient pact saw the rebirth of a legend. Roboute Guilliman, the long-absent Primarch of the Ultramarines, has returned to the battlefields of the grim future to lead the Imperium in its darkest hour. Meanwhile, the awakening of Ynnead, the God of the Dead, has given the Eldar a chance to escape the soul-draining attention of their race’s great nemesis, Slaanesh, by embracing a cycle of death and rebirth.
The disparate forces of the Imperium converge on the fortress world of Cadia as the armies of the Chaos Gods, led by Abaddon the Despoiler, hurtle towards it on a mission to tear reality asunder and carve a Crimson Path all the way from the Eye of Terror to Holy Terra itself. Saint Celestine, Inquisitor Greyfax and Belisarius Cawl join their causes in Cadia’s defence as the Dark Gods see millennia of plans come together at last.
When Yvraine finds herself near death in the fighting pits of Commorragh, she is touched by the nascent energy of Ynnead – Aeldari God of the Dead – and restored. As Yvraine, her champion the Visarch, and a group of her followers flee through the webway, they race toward Craftworld Biel-Tan ahead of the Daemons that pursue them. The Yncarne – Avatar of Ynnead – is summoned in defence of the craftworld, but the cost is high.
After the Celestinian crusade is rescued by the Ynnari, the uneasy allies travel through the webway to Ultramar to restore Roboute Guilliman to his place as Lord Commander of the Imperium. The Primarch embarks on a journey to Terra alongside the newest Grand Master of the Grey Knights, Voldus, and the Fallen Dark Angel, Cypher, fighting all manner of Daemons, both in the Warp and his own mind, to get there.