Led by the Emperor’s superhuman progeny, the primarchs, the vast armies of Earth have conquered the galaxy in the Great Crusade. The Emperor’s elite warriors, the heroic and battle-hardened Space Marines, have smashed all aliens, tyrant despots and traitors into compliance. Gleaming citadels of marble and gold celebrate their many victories. Triumphs are raised on a million worlds to record their epic deeds, but such vainglory will not last…

Rebellion looms when the Primarch Horus, he who once stood by the side of the Emperor, is tempted by the Chaos gods. Horus’s defection will shake the foundations of the nascent Imperium and take it to the edge of annihilation. As the flames of war spread across the galaxy, mankind’s champions will be put to the ultimate test, as brother faces brother and the universe trembles with the beat of war.