Sanguinius - Great Angel, most beloved of all the Primarchs, his mighty exploits are celebrated throughout the Imperium as the Crusade into the Void expands. 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 disgraced chronicler arrives with the expeditionary fleets to record the deeds Primarch, he has to work hard to uncover the truth behind the legends. As he joins the IX Legion in war against the Emperor's enemies, 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.