Prince Naveen is cursed by the evil witch doctor Dr. Facilier, which transforms him into a frog. This curse is a result of Dr. Facilier's desire to gain power and wealth, and it prevents Naveen from returning to his human form unless he receives a true kiss from a princess.

Tiana becomes a frog after she kisses Prince Naveen, believing he is a human prince. However, due to a misunderstanding, she does not realize that the kiss is meant to break his curse. Instead, the kiss causes her to transform into a frog as well, leading to their shared adventure.

Ray, the firefly, plays a crucial role in the story as a guide and friend to Tiana and Naveen. He is deeply in love with a star named Evangeline, which symbolizes his longing and hope. Ray's character adds emotional depth to the narrative, especially when he sacrifices himself to help Tiana and Naveen, showcasing themes of love and friendship.

Dr. Facilier, also known as the Shadow Man, is the main antagonist of the film. He uses dark magic and voodoo to manipulate others for his own gain. His desire to control Prince Naveen and Tiana drives much of the plot, as he seeks to capture their souls to fulfill his ambitions, creating tension and conflict throughout the story.

Tiana's dream of opening her own restaurant, which she plans to name 'Tiana's Place,' is a central motivation for her character. It reflects her hardworking nature and determination to achieve her goals, stemming from her father's legacy. This dream shapes her actions and decisions throughout the film, highlighting her growth as she learns to balance ambition with love and friendship.