It is the 42nd Millennium. For more than a hundred centuries the Emperor of Mankind has sat immobile on the Golden Throne of Terra. His Imperium spans the galaxy, yet it has been split in two by the Forces of Chaos after the Fall of Cadia and the opening of the Cicatrix Maledictum. Yet, with the tear in reality, opened by the malevolence of the four Dark Gods, something unexpected emerged into this reality. Something not within the plans of any player of the Great Game.

An ordinary man, born in another time and another place, emerges in the depths of a Hive World. Not as himself, but as a single spore of the most horrific of parasites.

The Flood has come to Warhammer 40k.