ef - a tale of melodies

As a young boy, Phoron met a spirit named Corticarte Apa Lagranges after she heard his song one night. Now, twelve years later, Phoron attends the Tolvas Commandia Academy, where humans train to become Dantists – people who can control spirits with music. One day, while unsuccessfully practicing a melody, Phoron sings the same song from all those years ago and not only does he manage to summon Corticarte to his side, but also makes a contract with her! Now he is bound to the temperamental spirit and, alongside his friends, Phoron must learn exactly what it means to perform a Commandia. But with a dark threat approaching, is it possible that this hapless orphan could actually be the key to preventing disaster?