Commissar Colonel Ibram Gaunt spent a year fighting as part of the underground resistance on the enemy-held world of Gereon. When he left, he promised that he would lead the forces of the Imperium to free the people of Gereon from their oppressors. Now he is back, with a crusading army at his back, but he finds a world devastated by war and a people irrevocably corrupted by the taint of Chaos. Now Gaunt must fight to save Gereon not only from the enemy, but from the Imperium itself.