Two different students - a successful but aloof academic and a rebellious but kindhearted delinquent - form a friendship through their love for music.

Schoolgirls discover that they have been given the ability to materialize weapons and control robotic beasts called "Children" to stop an evil organization from their plans of domination.

Shuichi Nitori transfers to a new elementary school, and there, meets Yoshino Takatsuki. The two children discover they share a similar secret.