Barbie plays the beautiful Princess Genevieve, who, with her eleven dancing princess sisters, discovers a secret entrance to an amazing, magical world where wishes come true. However, there's trouble in the real world, where their father is in danger of losing his kingdom, and the sisters must work together to help him.

Ariel is a fun-loving and mischievous mermaid who is enchanted with all things human. Disregarding her father's order to stay away from the world above the sea, she swims to the surface and, in a raging storm, rescues Prince Eric, the man of her dreams. Determined to be human, she strikes a bargain with the devious seawitch, Ursula, and trades her fins and beautiful voice for legs. With her best friend Flounder, and her reluctant chaperone Sebastian...