She is 12 years old and King Triton and Queen Athena's granddaughter, Ariel and Eric's daughter and the niece of Attina, Alana, Adella, Aquata, Arista and Andrina. Taking after her mother, she has an adventurous and rebellious streak. She has long black hair like her father styled in a ponytail and a red tail with pink fins when she's a mermaid. She learns how to talk to animals due to her mermaid heritage (however she is unaware of it).
When Melody is an infant, her parents sail out to sea and is presented to King Triton. When the proud new grandfather sees her he instantly loves her calling her "His precious Melody", and gives her a seashell locket, which, when opened, plays the melody of "Down to the sea" and shows a moving image of the underwater city Atlantica. The celebration is interrupted by Morgana, who threatens to hurt Melody if Triton does not hand over the trident which Triton almost agrees to do in order to save her. He ends up not having to when Ariel grabs Eric's sword and cuts the hatch to knock out Morgana and he retrieves Melody. When Morgana escapes, Ariel decides that until Morgana is found the sea would be too dangerous for Melody, and vows to keep all knowledge of the sea from her, including her Grandfather, late grandmother, and her aunts. Ariel heartbroken gives her father the locket he had given to Melody. A baby Melody looks back at her sad grandfather who then ask Sebastian to watch over Melody (just like he had done for Ariel).
Melody grows up banned from entering the sea, and isn't told the reason why. This causes a misunderstanding to exist between her and Ariel, who refuses to explain the truth to Melody.Making Melody believe that Ariel hated the sea and could not or would not understand her love of it. By her 12th birthday, she had been regularly secretly sneaking out to swim in the sea against her mother and fathers wishes. When Melody finds her locket on the day of her 12th birthday she finds her name on it and the image of Atlantica when she opens it. Melody begins to question Ariel as she had told her Atlantica was "Just and old fish tale." Ariel however panics when she hears this and simply yells at Melody for her disobedience that it was dangerous in the sea (like how her father had yelled at her). Melody ends the argument by telling her mother "How would you know? You've never even been in it." Melody then runs off from her room, and Eric then tells Ariel that the time had come to tell her the truth. To which Ariel agrees that "It's time I trusted her with the truth" before she can however Melody runs away from the royal palace.