In her attempts to stop Diva's plan of turning all of mankind into Chiropterans, Saya makes her way to the United States. Despite her forced rest, the time for action draws near. Meanwhile, Diva, carrying Riku's children, makes preparations for the birth of the queens of the next generation! With the fate of humanity resting with the two queens, who will rise and who will fall in the final showdown?! And what of the "promise" Saya made with Haji?