Battle for the Abyss — Ben Counter

NEWS OF HORUS's treachery is in the open, and a time of testing has come. As Horus deploys his forces, loyalist Astartes learn that the Wordbearers are sending a fleet to Ultramar, home of the Ultramarines. Unless they can intercept and destroy it, the Ultramarines may suffer a blow from which they will never recover.

Battle for the Abyss continues the epic tale of the Horus Heresy, a galactic civil war that threatened to bring about the extinction of humanity.