Satsuki Kakeru is unsure what to do when the Sky turns red and the Moon turns black, and the streets are filled with monsters. Yuka, his best friend, and Satsuki Kakeru try to figure out why they were sent to this strange place, which seems empty to them.
Kakeru and Yuka thought it was a dream when the “Red Night” ends. But then it happens again, and they find themselves in dangerous situations. They are joined by four other people in the same situation: Kusakabe Misuzu is an expert swordswoman; Tachibana Kukuri is a strange mute girl that looks very much like Kakeru’s sister; Hirohara Yukiko is a vibrant young girl whose personality changes to that of a cold murder when her glasses have been removed; and Tajima Takahisa who is a young pyrokineticist.
The six survivors band together to survive, and they discover the mysterious world. But things turn sour when six shadows appear in front of them.