Melody, daughter of Ariel and Eric, was led to the sea witch Morgana by her evil sidekick Undertow so she can ask her for her help, having been told by Undertow that Morgana has great magic powers. It was there that Morgana turned Melody into a mermaid but temporarily as part of her plan to manipulate the young girl to steal the trident that belonged to her grandfather, the sea king Triton of Atlantica.
After successfully tricking Melody into giving her the trident, Morgana rose out of her ice cave and declared herself queen and ruler of the seas. She then magically transformed her cave into a huge icy palace with the trident, while all those who tried to resist her were subdued, including Prince Eric and King Triton. Melody, however, successfully retrieved the trident back from her and returned it to her grandfather, Triton, who imprisoned Morgana in a block of ice, which then sunk to the bottom of the ocean while her ice palace crumbled and collapsed.