Barbie & the Diamond Castle is a 2008 direct-to-video computer-animated musical film directed by Gino Nichele and produced by Mattel Entertainment with Rainmaker Entertainment. It first premiered on Nickelodeon on September 7, 2008, and it was later released to DVD on September 9, 2008. The thirteenth entry in the Barbie film series, the film features the voice of Kelly Sheridan as Barbie and the cover of the song "Connected" recorded by Katharine McPhee. It follows the story of Liana and Alexa (the in-universe roles of the dolls, Barbie and Teresa) on their journey to find the mysterious diamond castle. Official description "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." Plot The story is told by Barbie and her best friend Teresa to Barbie's sister, Stacie, who had a fight with her own friend, Courtney. This is to teach Stacie the power of friendship. Liana and Alexa are two friends who live in a cottage, where they grow and sell flowers for a living. They both share the same love for music. One day, they find two heart-shaped stones and make them into necklaces to symbolize their friendship. That evening, a storm rolls in, destroying their garden. The next day, Liana offers her food to a poor, old woman who gives them a mirror in exchange. Later, the two hear a voice from the mirror and find a girl inside it named Melody. The trio bond over music and Melody teaches them a song of her own, but are soon attacked by a dragon named Slyder. They manage to escape him, but their cottage catches fire and burns down. Melody explains that she was once the apprentice of the three Muses who lived in the Diamond Castle. One of the Muses, Lydia, turned evil and planned to take the Diamond castle for herself. After hiding the castle and entrusting Melody with its key,