From publisher blurb:
A mouldering pit. Below the wreck of its sculpted capstone a stair winds sodden into gloom where a rancid sump rises, over walls sunk with hollows of life in death. Gibberings echo, and words in unknown tongues.
Condensed to one page for slipping in among other materials, this sandbox-oriented content is intended as an easily absorbed framework for improvisation to be adapted by the user as preferred for a wider setting and specific system.
It presents core ideas and key numbers to fall back on, with general approaches that can be applied in other situations.
The content covers map generation on the fly for an abstracted pit as well as suggestions for aspects of the locality, including occupants, pit structure, a potentially transformative slumber, a surviving builder and accelerated decay.
The pit could be detailed using Elaboration: Structure & Surface and possibly Being: More or Less Fantastical Olde Worlde Technologies, the sump using Elaboration: Atmosphere & Liquid.