[[quoteright:344:http://static.tvtropes.org/pmwiki/pub/images/diamondcastlecropped_8928.JPG]]

In this [[DirectToVideo direct-to-DVD]] movie of 2008, Franchise/{{Barbie}} and Teresa tell Stacie the story of two best friends, Liana and Alexa. Although the two girls do not have much, they have each other and a love of music. It gets worse when a nasty storm destroys all the flowers they would usually sell, but an act of kindness grants them a magic mirror.

Inside the mirror dwells apprentice muse Melody, who used the mirror as a means of escaping evil muse Lydia, who intends to grab the key to the muses' Diamond Castle and plunge the world into a state of grim darkness.

Now, Liana and Alexa must journey to the Diamond Castle themselves and stop Lydia from controlling all the world's music and dooming it to darkness forever.
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!!Includes examples of:

* AllTrollsAreDifferent: This one poses a riddle to cross the rainbow bridge. The penalty for failure is being eaten.
* TheApprentice: Melody is an apprentice muse.
* AwardBaitSong: "Connected," "We're Gonna Find It," and "Two Voices, One Song."
* AwesomeMomentOfCrowning: Alexa and Liana's coronations as princesses of music.
* BadIsGoodAndGoodIsBad: Lydia's extended VillainSong.
* BetterToDieThanBeKilled: [[spoiler:Melody shatters the [[SealedGoodInACan mirror]] rather than let Lydia get the Diamond Castle.]]
* BlackMagic: Lydia's magic is this.
* BlondeBrunetteRedhead: Alexa, Liana, and Melody, respectively.
* {{Brainwashed}}: Lydia uses a hypnosis spell on various characters to get the information she needs.
* BumblingSidekick: Slyder, to Lydia. He retrieves the wrong mirror and sets the girls' house on fire by mistake. His leitmotif is a silly tuba theme, too.
* TheCallKnowsWhereYouLive: The girls are forced to go on their adventure when their house burns down.
* CharacterNameAndTheNounPhrase
* CosmicKeystone: The Diamond Castle and the muses' instruments.
* DeadlyFireworksDisplay: Lydia's spell backfiring, which causes her to vanish in sparkles of light.
* DeflectorShields: The magical barrier produced by the necklaces worn by Liana and Alexa.
* DisneyDeath: [[spoiler: Lydia appears to die in a magical whirlpool, but returns at the climax]].
* TheDragon: Slyder is a literal version.
* DragonRider: Lydia rides SLyder to get around.
* EasingIntoTheAdventure: It takes a while before the girls leave for their adventure.
* ErmineCapeEffect
* EverythingsBetterWithPrincesses: Why not do the most logical thing and just make Alexa and Liana muses as well? Because then they wouldn't be princesses.
* EverythingsBetterWithSparkles
* EvilAlwaysTriumphsInTheMiddle: Despite the attempts of the heroines to keep Melody out of Lydia's clutches, the evil muse gets her hands on the girl-in-the-mirror and nearly gets her to give up the location of the Diamond Castle before Liana and Alexa arrive to save the day.
* EvilCostumeSwitch: Averted, as Lydia is already wearing a pretty evil-looking outfit in a flashback.
* EvilGloating: Lydia engages in this a lot. Her VillainSong is sung to the statues of the muses she imprisoned.
* EvilMakeover: After turning evil, Lydia casts a spell on her flute to make it match her outfit.
* EvilPlan: Lydia has one to find the Diamond Castle and control all music.
* EvilRedhead: Lydia has dark red hair and is quite evil.
* FairyTale
* FakinMacGuffin: Liana leaves a normal mirror for Slyder to retrieve while Alexa keeps Melody's mirror safe.
* FantasyKitchenSink: This movie has flying serpents, witches, good and evil magic, trolls, and muses.
* FeudEpisode: Alexa and Liana part ways when Alexa wants to stay at an opulent mansion that has been given to them and Liana wants to continue to the Diamond Castle and save the world.
* TheFinalTemptation: Alexa and Liana come across a mansion with everything they could ever want. Alexa wants to stay, but Liana goes on ahead.
* FramingDevice: Barbie and Teresa tell the story to Stacie, who's angry at one of her friends.
* FriendshipMoment: Liana is able to snap Alexa out of the villain's mind-control spell by replacing her necklace and reciting the friendship chant they made up earlier in the film.
* FriendshipSong: "Connected," "We're Gonna Find It," and "Believe."
* GettingCrapPastTheRadar: Lydia's extended villain song has her singing that she loves ''dogs with rabies''.
* GiantFlyer: Slyder for Lydia, and the Pegasi belonging to the other muses.
** [[WesternAnimation/BarbieAndTheMagicOfPegasus Brietta]] makes a cameo in the HilariousOuttakes.
* HandsomeLech: Jeremy and Ian unsuccessfully try to woo the girls with a song.
* {{Herald}}: Melody.
* HeteroSexualLifePartners: Liana and Alexa, though the {{Subtext}}...
* HappilyEverAfter
* HoistByHisOwnPetard: Lydia is done in by her own spell. [[spoiler:''Twice''.]]
* HostageForMcGuffin: Alexa, for the mirror.
* HypnotizeThePrincess: Lydia hypnotizes Alexa to give her the mirror and nearly walk off a cliff to her death.
* InsistentTerminology: Slyder is always referred to as a serpent, not a dragon.
* ItsAllAboutMe: Lydia's motive.
* JustBetweenYouAndMe: Lydia, after capturing Alexa, takes the time to explain exactly how she tricked her because she knows that Alexa took off the necklace that warded off her mind-control spell.
* KarmicDeath: Lydia turned the other muses to stone, and she and Slyder are turned into stone at the end.
* KneelBeforeZod: Lydia sings that all will bow to her once she rules the Diamond Castle.
* LargeHam: Lydia can't go one sentence without sounding overconfident and sure of her victory.
* LeastRhymableWord: LoungeLizard twins Jeremy and Ian are alternating lyrics in a song to charm the heroines. At one point Jeremy ends a line with the word "orange," and Ian quips, "You know perfectly well nothing rhymes with orange."
* LimitedWardrobe: Alexa and Liana only wear two dresses, which is unusual for a Barbie film.
* LoveableRogue: Ian and Jeremy fail to impress the heroines at first, and show up late to their own gig.
* LoungeLizard: Jeremy and Ian, who try to serenade Alexa and Liana with a song.
* MacGuffinLocation: The titular castle, which creates every kind of music. Finding it is Lydia's goal.
* MagicMirror: Melody hid inside an ordinary mirror, which turned it into a magic one.
* MagicMusic: Music is a source of great magic in this world.
* MagicalLand: The land Liana and Alexa live in.
* MeaningfulName: Melody, who is a musical apprentice, and later becomes a Muse herself.
* MementoMacGuffin: The necklaces, which act as a sign of friendship between Alexa and Liana.
* MindControlEyes: People Lydia hypnotizes get these.
* MindControlMusic: Lydia uses her flute to brainwash people.
* TheMuse: The muses guard all music and watch as new songs are created.
* MusicalChores: Alexa and Liana sing as they clean up the damage done to their garden during a storm.
* NotQuiteDead: Lydia appears to die when her spell backfires, causing her to vanish, but she reappears in the finale.
* ObviouslyEvil: Lydia, even before officially turning on her fellow muses, dresses in an outfit that should have tipped them off.
* OhCrap: Lydia gets several of these moments when her spells won't work.
* PimpedOutDress: Alexa and Liana gain these at the end.
* PinkMeansFeminine: Alexa wears a pink peasant dress, and in the finale both girls' dresses have pink as a major color.
* PowerCrystal: The Diamond Castle is covered with them. Each crystal represents a song.
* ThePowerOfFriendship: This powers the lockets; if one is missing the magical barriers will not work.
* ThePowerOfRock: Ian and Jeremy get magical electric guitars at the end.
* PreciousPuppies: The girls find a couple dogs, just to make things cuter.
* PrincessesPreferPink
* ReturningTheHandkerchief: Jeremy and Ian find Liana's handkerchief after she and Alexa spurn their advances, and they use it as an excuse to follow after the girls.
* RichesToRags: The girls return from the Diamond Castle to their simple lives selling flowers; their dresses even change back to normal.
* RidiculouslyCuteCritter: Lily and Sparkles, two puppies who accompany the girls.
* RomanticTwoGirlFriendship: Alexa and Liana live together, sing together, and do everything together. They have more chemistry between each other than with their love interests, Ian and Jeremy.
* SceneryPorn: The locations are very pretty, the Valley of Flowers in particular.
* SealedGoodInACan: Melody is sealed in a mirror.
* SicklyGreenGlow: Lydia's magic is this color.
* SingleMindedTwins: Ian and Jeremy often finish each other's sentences.
* SmugSnake: Lydia is often very overconfident and assured of impending victory, which makes her reactions whens something goes wrong quite funny.
* SorryImLate: Ian's quip when the twins rescue the girls from Slyder.
* SourceMusic: Despite being billed as a "musical fairy tale," only one of the songs can be considered non-diegetic: the villain's song, "Wonderful Me." And even that may be diegetic, as her minion applauds at the end.
* SuspiciouslyAproposMusic: Alexa and Liana ask Melody to teach them her favorite song, which turns out to be the key to the Diamond Castle.
** They also sing for their supper in an inn, with lyrics that match their current situation ("We're Gonna Find It"). At that same inn, Jeremy and Ian improvise a song to hit on the girls.
* SycophanticServant: Slyder is completely devoted to Lydia and often tells her how wonderful she is.
* TakeOverTheWorld: Or in Lydia's case, taking over Diamond Castle and all the world's music.
* TakenForGranite: Lydia freezes the other muses this way. [[spoiler:It happens to her and Slyder at the end]].
* TeamPet: Lily and Sparkles, two cute puppies who help the girls at times.
* TheyWastedAPerfectlyGoodSandwich: Despite being hungry enough to play at an inn for their dinner, Alexa and Liana soon leave the food behind to go to the Diamond Castle.
* TimmyInAWell: [[spoiler:Sparkles leads the twins to the girls, Lily picks up Alexa's necklace and drops it over the cliff to the girls]].
* TitleDrop: In one song, and the [[MacGuffinLocation Castle itself]].
* ToylessToylineCharacter: Characters that appear for less than three minutes got dolls, yet Lydia got nothing.
* TrollBridge: A troll guards the Rainbow Bridge.
* TwinBanter: Between Ian and Jeremy throughout the movie.
* VainSorceress: Lydia wants to be the world's only Muse, and keeps the mirror Slyder retrieves to look at herself.
* VillainSong: "Wonderful Me" by Lydia.
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