From publisher blurb: The Tomb of Rellannick has been abandoned for decades. Once a holy place, it has fallen into disrepair, and whlie still known throughout the desert, few travel to the tomb. Now, word is circulating that long lost knowledge and relics are hidden at the tomb. Hidden Knowledge can be used as an adventure in any campaign world, or played as a sandbox in Hellebarde's default setting. Written and tested with Castles and Crusades RPG, notes are provided for conversion to other OSR systems. Forgotten Knowledge can be used stand-alone or as part of the Exterris Adventure Tome AT-5 (AT-5 plus ONA-17 through ONA-20).