Ariel is a beautiful mermaid princess with an even more beautiful voice, who just happens to be enthralled with the human world so much that she disobeys her father to visit the surface. When she rescues a handsome prince from drowning, the sea-witch Ursula recognizes an opportunity to tempt the naive girl and overthrow the kingdom at the same time.

The youngest of King Triton's daughters, and the most defiant, Ariel longs to find out more about the world beyond the sea, and while visiting the surface, falls for the dashing Prince Eric. While mermaids are forbidden to interact with humans, Ariel must follow her heart. She makes a deal with the evil sea witch, Ursula, which gives her a chance to experience life on land, but ultimately places her life and her father's crown in jeopardy.