Young Calypso is obsessed with the world above the waves. This causes problems in the undersea world ruled by the sea witch Ursula especially since Calypso is a mermaid. Even worse, she has fallen in love with a human prince she rescued from a terrible storm! Calypso is determined to find a way to be with her love, even if it means leaving the sea and making a deal with evil Ursula. To top it off, Prince Airwick has his own troubles, with an overbearing mother and two scheming ministers out to skim the royal treasury for as much as they can take. Will Calypso’s friends, like Shellie the Crab, Katy Perrywinkle and of course her helpful, if slightly menacing Codfather, be able to turn the tide in her favour?