The masters of the Doom Eagles Space Marines Chapter descend upon the world of Tranzia to honour a batch of new recruits who will lead the Chapter into the next generation. As they make planetfall, the world rises up against them in a rebellion organised by the alien Tau. But something else lurks behind the xenos, a horror that has haunted the Imperium since its very beginnings. The Doom Eagles and their Adepta Sororitas allies are thrust into a race against time to discover the true architect of the Tranzia Rebellion before the entire world is consumed by darkness.