One night, a mysterious object falls from the sky in a flash of light. College student Ryo Kazama (Masahiro Inoue) rushes to the scene and finds a woman lying there who looks exactly like his classmate, Saya Saeki (Haruki Iwata), whom he has a crush on. However, the woman is not Saya, she's actually a military combat android bio-replicant named Eve, who has been released into the city due to a malfunction in a mysterious facility.