From publisher blurb:
A 5th Edition Mini-Dungeon for 4-5 characters of level 11
Deep in the frozen wastes, a fire giant outcast named Frexxis sold his soul to the ice devil Scerlyndir, plotting to dominate his old tribe and to enslave a nearby clan of frost giants. In a partially submerged glacial complex, carved by thermal undercurrents heated by volcanic activity deep below the surface, Scerlyndir performs diabolic rituals, breeding fell beasts to support Frexxis in his goals. When all is complete, Frexxis will emerge from his icy purgatory to seek glory. Local hunters notice the absence of their traditional quarry and speak of the nearby frozen caverns (parts of which are often flooded with icy water) with fear and trepidation.