Where The Machines Wait, softback Arcana of the Ancients adventure for D&D 5th edition and Numenera, by Bruce R. Cordell
“A vast underground ruin, filled with dangers and treasures unlike any seen before!
They call it the Grave of the Machines. An underground mausoleum of the Ancients, filled with their wondrous devices and strange magic. Those bold enough to venture into its depths (and capable enough to return) spin tales of sights and encounters so astonishing they could not possibly be boasts or mere fiction. And they say its riches are as vast and unfathomable as its depths.
Venture into the Grave of the Machines, if you dare, for adventure unlike any you’ll find in typical ruins or dungeons. Who knows what you’ll discover? Strange creatures? Riches beyond measure? Powerful artifacts? Perhaps all of that—and perhaps terrors that have lain dormant for aeons, dreaming of the day when they’ll be awakened to again walk the surface of the world.
Where the Machines Wait is a 5e mega-adventure for characters of roughly 5th level. It can be played as a series of short ventures into the Grave of the Machines, easily placed between other adventures in your campaign. Its deeper plotline can be introduced at any time—or you can ignore it and explore the ruin. Where the Machines Wait includes new creatures, new items, and a new playable species of mechanical, construct-like characters: the surk.
Numenera players can also delve into the Grave of the Machines: Where the Machines Wait includes complete conversion notes for Numenera and the Cypher System.”