From publisher blurb:
Slaves were used to excavate a hole beneath the earth, and when the hole was complete the slaves were trapped therein by their cruel master, Nergal.
A heartless host of executioners were sent into the pit and the slaves were killed, their bodies drained of blood, their flesh burned away.
Their bones and skulls became bricks; the soot, slurry and ash of their remains became mortar. And with these the cruel master constructed the walls of a labyrinth within the pit.
Their life blood Nergal poured into a vessel and this he positioned at the heart of the labyrinth. And the souls of the dead were in the vessel, an obelisk forged of blood. The labyrinth remains, though Nergal is long gone from the world. Yet his evil prevails in the form of the labyrinth of blood and bones, a dark and living thing with black ambitions.