From publisher blurb:
The northern waters are a fickle mistress along the shores of Castiel, the goddess Innak their only master. They can carry you to great adventure or pull you under into the darkness below. Innak’s children who tend her vast kingdom care little for mortal lives and less for their motivations. But when a captain dares to insult one by stealing a sacred item, a vengeful curse finds him and his shipmates, bringing them to ruin.
Cackles from the Thunder Caves is a Q-Crawl, or Quick-Crawl, that can be run for a group of four to six players with 5th-level characters. This crawl would be considered a ‘medium’ to ‘hard’ encounter.