One day, the main character "Nagisa Kujo" is attacked by mysterious men in black and taken to an underground facility. The eighth basement floor, the cryo-sleep room. Wake up!　Nagisa, wake up!　--Wake up! Nagisa wakes up to the voice of a mysterious girl. The voice calls herself "Mizuki" and says that she is speaking to Nagisa from the nanomachine implanted in her body. According to Mizuki's story, soon fighters of the evil organization "Shardark" will come to this room. Mizuki: "Anyway, let's leave this room. Can you move? Nagisa: "I'm a little heavy, but I feel fine. Mizuki: "Good. ......, let's go out of the room. Nagisa cooperates with Mizuki to escape from the mysterious underground organization.