Based on a game by CLOCKUP.

Cannone is a violin that entrances people. Ceillia is a violin that was created by the angels that seals Cannone.

Akio became a teacher for St. Cecillia Academy. He found Cannone sealed in the torture room under the chapel, he was fascinated by its power. The other violin picked a girl to use it`s powers to steal Cannone.

(Source: AnimeNfo)