Barbie performs Lumina, a mermaid lady with the ability to alter the colour of pearls. Cheerful and inventive, Lumina finds herself working in a mermaid salon customizing fabulous hairstyles. And when Lumina has the prospect to attend the royal ball, her pals adorn her with a robe match for a princess. On the ball, villains attempt to seize energy over the dominion, and Lumina finds inside herself an sudden energy that proves she is far more than a hair stylist.