The Blood Angels are just one of the many Space Marine chapters that defend humanity. They also carry a dark secret that they hide from the Imperium. When their Primarch Sanguinius died defending the Emperor from Horus this event leaves a psychic scar on the Blood Angels gene-seed, which is used to create the Space Marines. This psychic scar leaves the Blood Angels prone to reliving this traumatic event, which in turn makes them go mad with rage.
James Swallow in Deus Encarmine and Deus Sanguinius has told the story of these tragic fighters. On the remote cemetery planet of Cybele a group of Blood Angels clash with traitor marines from the Word Bearers. But things are not as straight forward as it first seems, as there are plots within plots as the Chaos forces have their own agenda for engaging the Blood Angels.
Within the Blood Angels events are also happening that threaten to split the whole Chapter. Battle-Brother Arkio performs heroic acts in battle that have his comrades talking about him being blessed by Sanguinius. Arkio's older sibling Rafen believes that something is amiss. This feeling is shared by experienced Battle-Sergeant Koris. Amongst this turmoil the trusted friend of the Blood Angels Inquisitor Stele of the Ordo Hereticus is playing his own game which may or may not relate to what is happening to Arkio.
this series has a slow build up but once it got going it was hard to put down.