READ IT BECAUSE
It contains one of the most mindblowing revelations of the Horus Heresy, about the true nature of the primarch Alpharius. Not only that, but it introduces a load of new players into the war, including the mysterious alien Cabal and the even more mysterious Perpetuals.
A Great War is coming, and it will engulf the Imperium of Man. The Space Marines of the Alpha Legion, the last and most secretive of all the Legiones Astartes brotherhoods, arrive on a heathen world to support the Imperial Army in a pacification campaign against strange and uncanny forces. But what drives the Alpha Legion? Can they be trusted, and what side will they choose when the Great War begins? Loyalties are put to the test, and the cunning schemes of an alien intelligence revealed.
Written by Dan Abnett