3 years after the events of The Little Mermaid II: Return to the Sea, King Triton has passed on from old age, and Ariel has claimed the crown and the trident , and her daughter, Melody is having time on sea and land, on land she is human, and in sea, she is a mermaid.
- Melody (Maggie Blue O'Hara) - The half-human/half-mermaid daughter of Eric and Ariel, she is now 15 years old and the main protagonist of the series, in human form, she wears dresses, while in mermaid form, she either wears pink seashell bra or a green seashell bra, and a pink flower in her hair.
In both forms, she is revealed to know some martial arts and can use a sword and a dagger as well as a spear.
- Tip and Dash (Max Casella and Stephen Furst) - Melody's 2 best friends and the "Flounders" of the series.
- Sebastian (Samuel E. Wright) -
- Ariel (Jodi Benson) - Eric's wife, Melody's mother, the queen of Atlantica who is now controls the trident and the secondary protagonist of the series.
- Eric (voiced by Rob Paulsen) – Ariel's husband, Melody's father and the third protagonist of the series.
- King Triton (Corey Burton) - comes like Jaga on Thundercats, and informs Ariel not to make the same Mistakes he made.
- Scylla (Angelina Jolie) - The main antagonist, she got killed in Season 1 finale.
- Lady Tramaine (Susan Blakeslee) - Scylla's servant, and top spy on the land.
- Cathy Catfish (Cindy Robinson) - Tip and Dash's scout to give Ariel messages.
|Episode Number||Title for the Episode||Synopsis|
|1||A New Beginning|
|4||Rise of the Morlocks|
|6||Love of Might|
|9||A Mother's Prayer|
|10||Light and Dark|
|11||The Lost Pricne|
|14||Princess and the Peas|