Buried Secrets is a collection of three small adventuring sites located near the the Stonehell megadungeon.

• Set underneath the ruined tower of a wizard is the monster-infested Modnar's Cellar,
  
• The Nest of Otrogg is a set of natural caves inhabited by a cult dedicated to the king of pests,
  
• and The Sanctuary of Cththonia is a sublevel of Stonehell where the PCs can rest in relative safety, as long as they behave.

Only the last of the three sites is set in Stonehell itself.