As a brief aside before we begin, I’ll freely admit I went into this in the worst of minds. To the old canon of the Horus Heresy, the Ultramarines involvement was over. They had fought at Calth, been given extended focus thanks to Lorgar and Angron’s crusade, and were trapped at Macragge. Beyond short stories the series should have been done with them, as the reason for their later strength was that they escaped the worst of the fighting. Diverting nearly the entire series to Macragge felt less like a true story development and more an effort to keep the spotlight on Games Workshop’s personal mascots than let them become side-lined. Something not helped by the continual shilling of the legion in other novels, keeping them in nothing but a superior-to-all light.
Thankfully for us, Unremembered Empire proves to be anything but an excuse to try and have the Ultramarines show off again; and is an excellent novel.
With the Ruinstorm created by Lorgar to isolate the five hundred worlds of Ultramar, the legion finds itself unable to contact the Imperium at large. Bloodied, beaten but unbowed, Guilliman enacts a desperate move to try and unite what’s left of any loyalist forces and prepare for the worst. Terra could be gone, he could be the last primarch alive, and for all he knows the remnants surrounding Maccrage could be all that is left. The Imperiumis over. The Imperium Secundus begins.