Unaware of the wider Heresy and following the Warmaster´s increasingly cryptic orders, Roboute Guilliman returns to Ultramar to muster his Legion for war against the orks massing in the Veridian system. Without warning, their supposed allies in the Word Bearers Legion launch a devastating invasion of Calth, scattering the Ultramarines fleet and slaughtering all who stand in their way. This confirms the worst scenario Guilliman can imagine - Lorgar means to settle their bitter rivalry once and for all. As the traitors summon foul daemonic hosts and all the forces of Chaos, the Ultramarines are drawn into a grim and deadly struggle in which neither side can prevail.
Dan Abnett is the author of the Horus Heresy novels The Unremembered Empire, Know No Fear and Prospero Burns, the last two of which were both New York Times bestsellers. He has written almost fifty novels, including the acclaimed Gaunt´s Ghosts series, and the Eisenhorn and Ravenor trilogies. He scripted Macragge´s Honour, the first Horus Heresy graphic novel, as well as numerous audio dramas and short stories set in the Warhammer 40,000 and Warhammer universes. He lives and works in Maidstone, Kent.