Saya and her team infiltrate the Yanbaru laboratory. David had learned that the U.S. military is conducting experiments underground to build artificial Chiroptera. There he discovers a mysterious keyword called "Delta 69". Then, a Chiropteran swoops down on Saya's party underground, where they can take no refuge. In order to escape from their subterranean trap, they will have to defeat the creature. Who can save Saya and her party from this desperate predicament?

At the experiment farm of Les Cinq Fleches Pharmaceutical, Saya is surrounded by child Chiroptera. But confronted with a mysterious humming coming from nowhere, the howling of the Chiroptera and a choking smell of blood, the girl goes berserk, and swings the sword at anything that comes into her view without even distinguishing between friend and enemy...

Saya and Hagi meet Solomon in the Zoo again. Hagi fiercely attacks him. Solomon skillfully handles Hagi. Solomon tells them that he is a chevalier and that chevaliers are trying to kill Saya. He also adds that his feelings are different from the wishes of his brothers. Around that time, David, Kai and Riku arrive at the Zoo...

Diva and Carl's attack puts the Red Shield Headquarters into great chaos. The ship's wall and floor are shattered and the black clad bodies lay everywhere. Saya faces difficulty as Carl continues to launch destructive attacks. Kai takes Riku to join David at a meeting point inside the ship, but...

The opera house has become a battleground. On the stage, the two Queens, Saya and Diva, clash with their swords. Meanwhile, at the wing of the stage, Hagi and Amshel, the two Chevaliers are facing each other. All this time outside the opera house, David and Kai are restrained in the TV broadcast van surrounded by the Chiroptera. To end the face off, David offers to play decoy.