Keep on the Borderlands: The Expansion

From publisher blurb: Keep on the Borderlands: The Expansion returns your players to the setting of one of the most notorious modules released by TSR, The Keep on the Borderlands. This adventure provides additional overland encounters, as well as additional Caves of Chaos for your players to explore. Return with us to the good ‘ol days when ’plot’ was just a four-letter word that stood between you and the treasure.