I Am Not Of Your Element (5E)

From publisher blurb: A 5th Edition Mini-Dungeon adventure for 4-6 PCs of Levels 13-14 Recently a wave of otherworldly energy flowed down a fault line far into the Underworld, dissipating where a fire giant monastery rested over a lava lake. The giants’ delving through the floor towards the lake had imperceptibly but irrevocably weakened the rock the ironclad stone halls sat on; it collapsed, taking down most structures, and even the stoutest giants finally drowned in the lava. One giant lives - the monastery’s Doombringer. Severely injured, the interplanar energies inhibited his natural healing. This far underground, the PCs sense the sulfurous heat long before reaching the carnage. They’re on a cliff edge, with lava dozens of feet below. Their route, towards the northeastern corner, should be a path across a cavern floor, but now it’s via a series of flat-topped columns rising from the lake below. Scorched stalagmites are dotted about. Three gigantic buildings are perilously close to the cliff ’s lip.