At the dawn of the forty-first millennium, Lord Commander Macharius and his forces embark upon the re-conquest of over a thousand worlds. A man of steel and fire, Macharius is the only one with the will to lead the massed armies of the Imperium to victory. As the crusade rolls onwards, it reaches the world of Karsk. In the city of Irongrad, the Imperial forces face the crusade's end, unless Macharius and his army can defeat the dreaded Angel of Fire. What ancient perils may yet lie outside the Imperium and the dominion of mankind?