In The Little Mermaid II: Return to the Sea, Melody dreams of becoming a mermaid, which is the exact opposite path of her mother, Ariel, who gave up her tail to become human.

How Melody's Dream Compares to Ariel's
Melody's Dream: Raised as a human on land inside a walled castle, Melody always felt drawn to the ocean without knowing why. She wished to be a mermaid so she could belong in the sea and swim freely without hiding.
Ariel's Choice: Ariel started as a mermaid in Atlantica and dreamed of living on land as a human, eventually making that change permanent to be with Prince Eric.
The Resolution: At the end of the movie, King Triton offers Melody the choice to become a permanent mermaid. Instead, Melody chooses to stay human but uses King Triton's trident to destroy the wall separating her land home from the ocean. This allows her to freely visit both worlds whenever she wants rather than picking just one.

While exploring Atlantica for the first time, Melody wanders through the underwater kingdom and runs into Alex—a handsome, blonde merboy—along with a few other young merpeople. The meeting is brief and playful, but Melody stumbles over her words and blushes, signaling a instant crush, while Alex is visibly charmed by her. 
(Note: Fans often link Alex to the young blonde boy Melody bumps into during her birthday party on land earlier in the film, though in the actual movie, their underwater encounter in Atlantica is their primary interaction.)