Relive the event that broke three whole Legions and set the stage for Horus’ march on Terra in Dropsite Massacre by John French, a fresh new perspective on the most notorious betrayal of the Horus Heresy. Rogal Dorn’s punitive fleet arrives in the Isstvan System to drag Warmaster Horus before the Emperor for judgement, but not all of the Legions assembled to break the Traitor army are assured in their loyalties, and before the day is done, a Primarch will lie dead on the black sands of the Urgall Depression.