Many years ago, the Order of the Soul Drinkers broke with the Adeptus Astartes, choosing their own path to serve the Emperor. Outcasts and rebels to the Imperium, they still serve it, protecting its worlds. Having intercepted a call for help from the imperial planet Vanqualis, which has been attacked by orcs, the commander of the order, Librarian Sarpedon, decides to go to the rescue, in the depths of his soul hoping to restore the good name of the order and return to the favor of the Imperium. But among the Drinkers, a new ambitious leader appears who wants to take the reins of power into his own hands. These problems are compounded by the appearance on Vanqualis of the Howling Griffons, a Space Marine order hunting the bearers of the Black Chalice. And myths and prejudices attribute the possession of the Grail of the Damned to the Order of Sarpedon. And the commander enters the war on three fronts.