Sanguinius is the Great Angel, the most dearly loved of the primarchs, and his magnificent deeds are celebrated throughout the Imperium as the Crusade presses deeper into the emptiness. Yet the origin of his legion is shrouded in secrets and rumors: his unique physical form is itself a mystery, and his home world of the Blood Angels—full of dangers—remains closed to everyone except his secluded people. One day, with the expeditionary fleets arrives a disgraced chronicler, summoned to record the primarch’s deeds, and he sets out to find the truth hidden behind legends. Accompanying the IX Legion in battles against the Emperor’s enemies, this inquisitive researcher learns much more than he expected—not only about the heroes of his work, but about the very nature of the Imperium itself.