Adventure in a weird and fantastical underworld in a place so far from the surface that the sun and sky are only legends, so vast no bounds can be placed on its dimensions or contents. Welcome to the Deep, Deep Down.

* An underworld add-on for any fantasy roleplaying system (or stands alone with its own built-in engine)

* Rules for dangerous journeys, generating weird peoples and places, and foraging strange fungus.

* Three modes of play: with a GM, collaboratively, or solo.