The Dragon Below

Publisher's blurb: DARE YOU ENTER THE CREEPING NAVE? In the depths of Valaara's sanctuary, the Order of the Emerald Claw harnesses ancient engines of destruction to wage war on the surface world. Only the Oracle of War can stop them now - if the adventurers can get it to work! Optimized for APL 16, this is the third in a trilogy of adventures, the Engines of War storyline.