The brutal war for Cadia is decided, as Lord Castellan Ursarkar Creed and the armies of the Imperium fight to halt the Thirteenth Black Crusade and prevent a calamity on a galactic scale.

Under almost constant besiegement by the daemonic hosts pouring from the Eye of Terror, Cadia stands as a bulwark against tyranny and death. Its fortresses and armies have held back the hordes of Chaos for centuries, but that grim defiance is about to reach its end. As Abaddon's Thirteenth Black Crusade batters Cadia's defences and the armies of the Imperium flock to reinforce this crucial world, a terrible ritual long in the making comes to fruition, and the delicate balance of this brutal war shifts... From the darkness, a hero rises to lead the beleaguered defenders, Lord Castellan Ursarkar Creed, but even with the armoured might of the Astra Militarum and the strength of the Adeptus Astartes at his side, it may not be enough to avert disaster and prevent the fall of Cadia. While Creed lives, there is hope. While there is breath in the body of a single defender, Cadia Stands... but for how much longer?