The story takes place at the world in which people continue their war against the "unknown" - the enemy of humanity. They are children, who have been evacuated to the cold sleep facility during the invasion by the "unknown" several decades ago. When they wake up from their slumber, they learn that their own bodies develop some supernatural forces. In order to protect the country from the "unknown" emerging from the Tokyo bay gate, the boys and girls wage battles in the defense cities of Tokyo, Kanagawa, and Chiba.
[Source: official website]