Princession Orchestra: Hibike! Princess no Sanjuusou

Alicepia is a mysterious country that has existed since ancient times. The inhabitants of Alicepia, the Alicepians, are fun-loving people, but one day, mysterious monsters called Jamaock appeared to threaten the peace of Alicepia. The story follows the "princesses" who never forget the song in their hearts, even when facing such danger. Source: ANN