Experience the pivotal moment that shattered three entire Legions and ignited Horus’ advance on Terra in Dropsite Massacre by John French, offering a fresh take on the infamous betrayal of the Horus Heresy. Rogal Dorn’s punitive fleet arrives in the Isstvan System to bring Warmaster Horus to account before the Emperor, yet not all Legions gathered to confront the Traitor forces remain loyal. By day’s end, a Primarch will fall on the black sands of the Urgall Depression.