King Neptune and an array of sea creatures come to the rescue of a mermaid captured by lecherous pirates.
After a short introduction, one of Neptune's mermaids is captured by a pirate ship, and their anchor chain entangles King Neptune; the various sea creatures launch a full-on assault on the pirate ship, and eventually the giant King himself gets free and creates major havoc for the ship.—Jon Reeves <jreeves@imdb.com>