After Dr. Ayanokoji's developed the Steel Angel, an artificial human with superhuman physical abilities, the Imperial Army wanted to use his new technology as a new form of warfare. However opposed to this Dr. Ayanokoji secretly developed a Steel Angel code named "Kurumi" that he wanted to one day use to advance human civilization. However when Nakahito Kagura is pressured into dare of sneaking into the Doctor's home he discovers Kurumi and awakens her with an accidental kiss. Now Kurumi has been entrusted to Nakahito and he must protect her against being discovered by the military.