Mark of Calth

In "Calth That Was" by Graham McNeill, the Ultramarines of the XIIIth Legion are unexpectedly betrayed by the XVIIth during a catastrophic event known as the Heresy, plunging them into chaos. As solar flares ravage the planet, the remaining survivors must confront the Word Bearers and their allies or risk damnation in the depths of the arcology shelters. This gripping novella chronicles the pivotal moments that will forever change Captain Ventanus and the fate of the Ultramarines Chapter for the next 10,000 years.