Barbie is back in a brand new underwater adventure! In the newest Barbie movie, Barbie plays Merliah, a popular surfing sensation . But everything changes when her hair starts turning pink and she can suddenly breathe underwater. Then she meets a dolphin named Zuma who reveals that Merliah is actually a mermaid princess. Merliah's mother, Queen Calissa, has been imprisoned by her evil sister Eris and the mermaid kingdom of Oceana is in trouble. Merliah will need the help of her above water friends and her new underwater friends to save Oceana! But first she'll have to learn what makes her different might be her greatest strength!