Storm of Iron

Few foes spark more fear and dread than the Chaos Space Marines. Nurturing a hatred that is millennia-old, they attack without mercy. Now hell has come to Hydra Cordatus, for a massive force of terrifying Iron Warriors, brutal assault troops of Chaos, have invaded the planet and lain siege to its mighty Imperial citadel. What prize could be worth so much bloodshed and how long can the defenders possibly hold out?