From publisher blurb:
This place sits on the border between the mundane world and the world of machines. It is a horrendous mishmash of metal mechanical components, contorted and broken and pressed to form this recognizable-but-alien cavern reeking of oil. This is a place where machine life is the norm, and biological meatbags are unwelcome, prone to a toxic demise. Many creatures found here are parodies of biological life, while yet others have discarded all such trappings for a pure mechanical state. Terrible screeches and clanking and whirring of horrible entities echo through these cavernous chambers. In these twisting halls of metal, there are treasures to be plundered, for where metal abounds, there’s sure to be gold.
These caverns are an expansion to the Descent into Madness megadungeon, being attached to ‘First Steps’ on the West and the ‘Vault of Wonders’ on the South. This sprawl has many subsections where various entities have settled in to ply their crafts. Some are more recognizable human imitations. Others are utterly alien. It includes of course many encounters of mechanical nature, a winding treasure hunt with hints that begins in room 59, a town of friendly robots to the east complete with the Robo-Drift DEATH RACE, gateways to other worlds, and more. Despite its mechanical nature, it is still loaded with plenty of magical items and probably too much treasure for the adventurer seeking their fortune!