As news of Horus's treachery spreads, the Great Crusade grinds to a halt as the primarchs and their Legions decide where their loyalty lies - with the Emperor, or the rebel Warmaster Horus. In this sequel to Descent of Angels, the Dark Angels, too, face a time of testing, both in the stars, and on their home world, Caliban. Civil war erupts as the planet strives to break from Imperial rule, and the Dark Angels are thrown into a deadly conflict where all that they know and trust is thrown into doubt!