This is the real headquarters of Anti-Entropy, a city established in the subspace, and the members of Anti-Entropy call it "The Ark". Kiana is now participating in an important meeting in the conference room of the Ark - Anti-Entropy has found signs of a major outpouring Schicksal, and their target is Kiana with Himeko and Theresa teacher a year ago. The investigated island is named "Sangharama". But after that, Schicksal also went there to investigate, but found nothing. Now Kiana knows from Anti-Entropy that there are relics of ancient times under this island, and this time, Schicksal dispatched again and went straight to Sangharama, and their target must be the underwater fortress. Even though they knew that this might be Otto's tactic to lead the snake out of the hole, they had to go because it was to help their friend, the middle-aged girl who voluntarily took all the pain for them. In the ruins of the Sangharama Fortress, there is still an area that the doctor has not yet explored, and there may be a prescription for the cure of Kyuusyou hidden there. Before confronting Schicksal, she has to say goodbye to someone. Thinking like this, Kiana walked into the ward where Kyuusyou was.