As the Imperial forces desperately hold out against an Ork onslaught, an elite squad of Kasrkin are sent on a special mission. Learn just what it means to pay the tithe and how not even catastrophe comes between the Administratum and their due.

As White Templars Space Marines attempt to repel an invasion by Tyranids on the world of Ystrad, an ominous Black Ship is inbound to retrieve their tithe of psychic souls. Will they collect their due?

As Sa'kan of the Salamanders continues his hunt for Illuminor Szeras, an Ultramarines Apothecary on a vital mission joins him. Can Sa'kan manage to put his duty before his need for vengeance?