From the front of the book: Sanity's Precipice is an adventure designed for five 25th level player characters (PCs), and is part of the D&D Delve Night kit. Please review the instructions for use of the D&D Delve Night kit before using this adventure. The adventure uses tiles from the DU3 : Caves of Carnage tile set. The adventure takes place in set of caves near the Sanity's Precipice, a sliver of elemental earth and fire that juts out over the Abyss.