This is B2.5: Caves of the Unknown (2018), an expansion to B2: Keep on the Borderlands produced for North Texas RPGCon 2018. This cave is indicated on the original module map with a notation that DMs could expand it with their own material if they wish. Charley Phipps wished! The main section of this module feels pretty in step with the original, perhaps with just a little more modern zip. There is a nice little werewolf encounter. Then the cave itself (really a cave system, tomb and chapel complex) is split pretty evenly between bugbears and undead, though there is a one-eyed living statue that seems suspiciously familiar…

Mike Badolato contributed details for three smaller cave locations — a bear den, a cave full of spiders and a small bandit encampment. Finally, Thom Wilson penned an alternate version of the original Keep’s lizardfolk encounter, fleshing what was originally a simple fight into a full-fledged side quest.

This is pretty great! Taken all together, it is a significant expansion to an already hefty original that enhances the experience. No small feat!