Barbie stars as Merliah, a surfer who learns a shocking secret: she's a mermaid! She and her dolphin friend set out for an undersea adventure to rescue her mother, the queen of Oceana. Merliah Summers is an avid surfer in Malibu. While participating in a surfing competition, Merliah loses concentration when her hair spontaneously streaks pink, and wipes out. While underwater, she discovers that she can breathe in water, and is approached by pink-purple dolphin named Zuma, who wants to talk to her. Merliah tells Break, her grandfather, of the incident. Break explains that Merliah's mother is a mermaid, and that Merliah was given to Break as a baby to raise because she was born with legs. Merliah doesn't believe him and goes to her friends Fallon and Hadley, telling them the story...