kiyoyo

In the distant future humanity is at war with a robotic civilization. The show follows the events in the Tempest Tower inhabited by the gynoid duchess Drossel von Flügel and the castle's butler Gedächtnis.

On his first day at his new school, twelve-year-old Ritsuka Aoyagi meets a mysterious twenty-year-old male named Soubi Agatsuma. Soubi claims to be a good friend of Ritsuka's brother, Seimei, who was murdered when Ritsuka was ten years old.