In the blood-soaked Sabbat Worlds Crusade, the massed ranks of the Imperium battle the dark forces of Chaos for dominion. At the forefront of this conflict are the Astra Militarum - untold numbers of ordinary Imperial Guard soldiers fighting to preserve the Emperor's holy realm. Colonel-Commissar Ibram Gaunt and the men of the Tanith First-and-Only are at the heart of this struggle, their specialist scouting role earning them the nickname 'the Ghosts'. From the holy world of Hagia to Phantine's aerial dome cities and the mud-filled trenches of Aexe Cardinal, Gaunt's Ghosts find themselves in the thick of the fighting time and again, charged with the most dangerous missions the crusade's commanders care to throw at them.