As Menou sets out to infiltrate Iron Chain with her former colleague Sahara, she leaves Akari under Momo’s protection. But instead of watching over Akari from the shadows, Momo decides to approach Akari directly! Meanwhile, deep in Iron Chain’s base, Menou faces the looming threat of one of the Four Major Human Errors, Mechanical Society… What is the final destination of these girls and their tangled threads of fate? Find out in this epic final volume!