Barbie and Teresa tell us the fairy tale story of Liana and Alexa, best friends who share everything including their love of music.
One day their simple lives change when they are given an enchanted mirror and befriend the girl trapped inside! To save their new friend, Liana and Alexa embark on a dangerous journey to the hidden Diamond Castle, that will put their friendship to the test. But through the power of song and with the companionship of two adorable puppies, the girls face their challenges together and learn that friendship is the true treasure.
Liana and Alexa (Barbie and Teresa) are best friends who share everything, including their love of singing. One day while walking through the forest home from the village, the girls meet an old beggar who gives them a magical mirror. As they clean the mirror and sing, a musical apprentice muse named Melody appears in the mirror's surface, and tells the girls about the secret of the Diamond Castle.