Touya Kumono attended Ransen Private High School, living his everyday life alongside his close friends Seishirou Hiiragi and Kasumi Einhart.

One day, Riko Utsugi, who had worked as an assistant to Kasumi's father, the scientist Herman, came to visit Kasumi's home.

Riko had come to protect Kasumi from Dice, an organization seeking to exploit her abilities. Shortly after her arrival, however, they were ambushed by the enemy. During the attack, Touya and Seishirou received an "Augment" from Riko and were forced into battle.

[Translated from wikipedia]