Samson IV is a hive world in the Hazeroth Abyss of the Calixis Sector. Recently, the ineptitude of Cardinal Dantius Landsholt has caused the power of the Ministorum to wane in the Hazeroth Sub, allowing many worlds to fall under the influence of other groups. The Adeptus Mechanicus has spread to Samson IV from the forge worlds of Idumea and Synford because of this.
The drug known as Holdfast, smuggled from the feudal world of Elros, is known as Puremind in the hives of Samson IV.