The opening trilogy perfectly sets the scene for everything that is to follow. The Great Crusade is drawing to a close and the Emperor returns to Terra, pronouncing Horus Warmaster...
Seduced by the promises of dark gods, Horus rejects his oaths to the Emperor and declares outright rebellion. The true beginning of the Horus Heresy starts here...
As Horus' treachery is revealed and several other Primarchs and their Legions join his cause, the struggle for the galaxy begins across multiple war fronts
As the loyalist Legions lay crippled and scattered, Horus and the other Traitor Primarches look to consolidate their power.
With the galaxy split in two by a furious warp storm, the loyalists engage in a desperate plan to form a second front in the event of diaster.
The loyal Primarchs begin to follow their own paths as they try to fight for mankind's freedom from tyranny. Oh, and, a note from JP - this is a bit of a "choose your own adventure" style scenario in that you can follow the story of the Raven Guard, the Salamanders or the White Scars. You could choose all three, but the whole point of this list is to acknowledge that no-one has enough time for that. So, instead, I am choosing for you: the White Scars. If you really want to know what books are recommended for the Raven Guard and the Salamanders, well, ask me. I'll tell you.
As the Traitors cut a swathe across the galaxy, the protectors of Terra look to their defence.
Forces on both sides of the war prepare for the inevitable attack on the Golden Throne and the Siege of Terra.
Everything has led to this moment... the greatest battle ever fought in the history of mankind begins, the very fate of the galaxy at stake.
So, uh, what that means in practice is that there's an entire follow-up mini-series, called "The Siege of Terra", comprised of 9 further books which you have to read all of. Sorry about that.
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