Sanguinius is the Great Angel, the most beloved of all primarchs, his mighty feats celebrated throughout the Imperium as the Crusade expanded into emptiness. However, the origins of his Legion are shrouded in mystery and rumor, his unique body is a mystery, and his dangerous homeworld remains inaccessible to all but his own secret people. When a self-deprecating chronicler arrives with the expeditionary fleets to record the acts of the primarch, he has to make a lot of efforts to reveal the truth behind the legends. Going with the IX Legion to war against the enemies of the Emperor, the inquisitive scientist learns much more than he expected - not only about the subjects of his research, but also about the nature of the Imperium itself.