After the devastation of Bhaal and the arrival of Roboute Guilliman with the Indomitus Crusade, Commander Dante, Master of the Blood Angels, was appointed regent of the entire Imperium-Nihilus. Working with Chapters that follow the Blood Angels, Dante orders the region around the Red Scar to be explored in preparation for the return of these stars to the rule of the Imperium. The mission led the Red Wings to Dulcis, a planet dangerously close to the Cicatrix Maledictum itself, the Great Rift. Almost destroyed by the Tyranids during the War for Baal and only partially replenished by the Primaris Space Marines, the Chapter of the Red Wings is unable to cope with what is happening in this world. Strange psychic phenomena and deadly xenos threaten the greatest hope of all the Blood Orders - the hope that the flaw in Sanguinius's gene-seed has finally been overcome. Drawn to Dulcis by the Black Rage, Astorath the Grim, High Chaplain and Redeemer of the Lost, comes to the aid of the Red Wings. But what he is about to discover will shake the order to its very foundation.