This is my version of the movie.
Ariel and Eric celebrate the birth of their newborn daughter Melody on a ship at sea. Ariel's father King Triton presents Melody with a magic locket. The party is interrupted by Morgana, sister of the deceased Ursula, who threatens to cause Melody harm, using her as leverage to get Triton's trident. Ariel and Eric work together to foil Morgana's plan.
Fearing Morgana and remembering Ursula, Ariel decides to withhold all knowledge of the sea world from Melody. The locket is tossed into the ocean, and a massive wall is built to separate the royal castle from the sea.
Twelve years later, Melody remains unaware of her mother’s mermaid heritage and is forbidden from ever going into the sea. However, she has been sneaking out the castle regularly to swim and one day finds her locket. Seeing her name on the locket, Melody wants to confronts her mother but fear that her mother will not have the anster. So she takes a boat and sails away from home. Her parents soon learn that she is gone, and Triton uses his magic to transform Ariel back into a mermaid to search for Melody.
Melody meets Morgana, who tells her that Atlantica castle in the locket is a part of her destiny, and that she is only half of what she really is. To Melody's surprise, Morgana says that she is actually part-mermaid, something that Melody believed to be an "old fish-tale". Using Ursula's old magic, Morgana turns Melody into a red-finned mermaid, and the delighted young girl jumps around for joy, unaware that she is just being used for a trap.
Meanwhile, Sebastian informs Ariel and Eric that Melody has run away to sea, and Ariel contacts her father, Triton, immediately. Eric prepares a search fleet on land, and Triton starts the sea search. With Eric's advice, Triton agrees to turn Ariel back into a mermaid so that she can help in the search for her daughter.
After enjoying her new power for a while, Melody revisits Morgana to thank her, but Morgana tells Melody that the spell is only temporary, and that the only way for her to become a permanent mermaid is to use the power of "her magic trident" which was "stolen years ago by an insane klepto-maniac". Melody agrees to try and get the trident back for Morgana, and Morgana gives her a map to Atlantica.
During the journey, Melody meets Tip the penguin. They head underwater to find the trident and take it for Morgana.
Meanwhile, Ariel, along with Triton and Sebastian, is reunited with her childhood friend, Flounder, who aid Ariel in her search. As they decide to take a rest for a while (other merman soldiers are searching for Melody throughout the ocean), they don't notice Melody and Tip sneak into the castle, determined to steal the trident from the one Melody does not know is her grandfather.
Avoiding Triton, Melody manages to take the trident from its stand and flees with Tip and Dash, but accidentally leaves behind her locket. Immediately knowing that Melody is somewhere nearby, Triton commands the search to continue, but Ariel and Flounder notice the flatsos swim off nearby, and tail them.
Eventually, Ariel and Flounder hightail the flatsos to Morgana's lair, and ask Scuttle the seagull to get backup, for they know that they will need it.
They found Melody and tries to stop Melody, but before Ariel can explain that Morgana is evil, Melody gives the trident to Morgana. With the trident in her grip, Morgana reveals her true intentions, grabs Ariel with her tentacle and holds her hostage and and blows Melody and Flounder into a hole where she traps them behind a trident-made layer of glass, but not before telling Melody that her mermaid time is almost up. Laughing maniacally, Morgana and Undertow leave the scene with Ariel, leaving Melody to die in front of Flounder.
Morgana uses the trident's magic to lord over the ocean, rising to the surface to gloat. Scuttle, Triton, Sebastian, and Eric arrive, and a battle ensues against Morgana and her minions. Meanwhile, Tip finally decide to rescue Melody and enter Morgana's lair, where he is confronted by Undertow. He went underwater to find Melody, but Undertow chases after Tip. Inside Morgana's traphole, Melody's mermaid time expires, and she comes close to drowning, since Flounder is not strong enough to break the glass. Then, they are rescued as Undertow suddenly comes crashing through the glass and bashing himself into the wall. Tip and Flounder gets Melody to the surface in time. They reach the surface and Melody manages to grab the trident and throw it back to Triton by climbing up the cliff on which Morgana is standing and sneaking up on her. Triton uses his trident to encase Morgana in a block of ice, which sinks underwater.
Melody reunites with her family, and Triton offers his granddaughter the option of becoming a mermaid permanently. Instead, she uses the trident to disintegrate the wall separating her home from the sea, reuniting the humans and the merpeople.
- Jodi Benson - Ariel
- Tara Storg - Melody
Down to the Sea - Airel, Eric, Grimby, Sebastain and Chores