Mizuki has been staying out later after school instead of going home. As she enters puberty and her body begins to change, her father's advances have become increasingly frequent. One day, when she returns home, she finds several unfamiliar pairs of shoes lined up at the entrance. "Welcome back. We've been waiting for you. Come here," a voice calls out—and inside, she sees a group of strange men. She tries to run, but is quickly caught and dragged into their circle.