Ariel, a young and adventurous mermaid princess, is fascinated with the human world. She spends her days collecting human artifacts and dreaming of life on land, much to the chagrin of her father, King Triton, who is wary of humans and has forbidden contact with them. During one of her explorations, Ariel rescues Prince Eric, a human, from a shipwreck and falls deeply in love with him. Desperate to be with her newfound love, Ariel makes a risky deal with Ursula, a sea witch, trading her beautiful voice for human legs.

Now able to walk on land but unable to speak, Ariel endeavors to win Prince Eric's heart within a tight deadline set by Ursula's spell. If she fails to receive the "kiss of true love," Ariel will belong to Ursula. Accompanied by her loyal fish friend Flounder and a comical crab named Sebastian, the mute Ariel navigates the nuances of the human world, trying to bridge the gap between her undersea life and her ambitions on land. Ariel's journey is fraught with challenges as she adapts to her new form while keeping her mermaid heritage a secret from Prince Eric and those around him.