Revenge on the Shinjo sisters…Masato gets his hands on the ○○ device and sets his childhood friend, the evil sisters, on a trap. Hina puts the choker handed to her by Serina around her neck, unaware that it is a ○○ device. When the ○○ device is activated, she speaks words that are the exact opposite of her will, and at the same time, her body reacts like a marionette. Masato commands her to enjoy the changes she undergoes, and manipulates her to his will. Then Serina appears, presses the button on the ○○ device, and Serina also surrenders in an instant. Having opened a new door, Hina and Serina discover the pleasure of being subjugated to ○○.