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.
Marcellite Garner
as Mermaids (voice) (uncredited)
Allan Watson
as King Neptune (voice) (uncredited)
Jack Bergman
as Effeminate Pirate (uncredited)
Dorothy Compton
as Mermaids (uncredited)
Beatrice Hagen
as Mermaids (uncredited)
Delos Jewkes
as Deep Basso (uncredited)
Mary Moder
as Mermaids (uncredited)
