Shuji and Chise are two Hokkaido high school students who are only getting to know one other. Then, without warning, a squadron of bombers from an unknown country bombs Sapporo. When the bombers are abruptly destroyed by a little red light drifting across the sky, all hope is lost. At this time, Shuji discovers that the person responsible for destroying the opposing forces is Chise, who shows herself to be a cyborg designed for mass devastation.