From the front cover:

Shadows stir beneath the earth. In Tower of Blood, the PCs discover that a subterranean gnomish tower has fallen to beings from the Plane of Shadow. Can a band of heroes drive this menace from the depths before it claims the unsuspecting world above?

This module details three distinct settings for adventure: a large cavern within which the three-level tower rests; two levels of mines below the tower; and the sinister lair of forces allied to the tower invaders. Tower of Blood also features two unique NPC foes, seven new magic items, and five new monsters. Tower of Blood can be run as a stand-alone adventure or as a sequel to RJK-1 Cairn of the Skeleton King.