Sion has declared that the class will engage in a battle royale, and anyone who fails to participate will forfeit their lives. After one classmate's schemes send Yogiri tumbling down to the seventh level, separating him and Tomochika just before the battle starts, the pair try to reunite as quickly as possible. Meanwhile, the quieter members of their class decide it's time to reveal their true strength. Things are complicated even further once Ayaka catches up just in time to join the fight, and the Underworld begins a transformation spurred on by Mana's newfound freedom. But as everything descends into chaos, there is one last spark of hope: The situation seems perfect for drawing Sion out and finally securing a meeting with her.