Of Honour and Iron — Ian St. Martin

The age of the Dark Imperium has begun, and the human race is poised on the brink of ruin. In their darkest hour, the Emperor's servants have achieved the impossible: the resurrection of the Primarch Roboute Guilliman. Now Lord Commander of the Imperium of Man, Guilliman marshals his forces in a desperate effort to drive back the predations of Chaos: the Indomitus Crusade. Dispatched ahead of the bulk of Guilliman's war fleets, Chaplain Helios of the Ultramarines is entrusted by the risen primarch with a mission of vital importance. Will he achieve a crucial victory for Guilliman in time, or will a millennia-old obsession spell his doom? And just what manner of weapons will be needed to wage the war to save mankind?