The story begins in the near future, where a social mobile network called the "Kizuna-Topia" (Bonds-Topia) controls all communication and surveillance in the wall-bound city.<br /><br />In this city, two sisters, Enna and Yayako, come face to face with the ongoing man-hunt for young, healthy children. The kidnappers take these kids to the white tower to extract their brains and sell their bodies. This man-hunt, led by the local police known as the "Jikei," is counteracted by the mysterious being only known as "The Witch."<br /><br />Enna, Yayako, and other residents of this city are trapped between the ongoing conflict between the Jikei and The Witch.