In 2045, the world is reeling from the aftermath of the Global Simultaneous Default, an economic catastrophe that shattered global stability, alongside the rapid advancement of artificial intelligence. This era is defined by the Sustainable War, a prolonged conflict engineered to persist indefinitely. Despite these challenges, the looming threat posed by advanced AI remains largely overlooked by the general public.
To address the cybercrimes perpetrated by the emerging Posthuman faction, Public Security Section 9, led by full-body cyborg Kusanagi Motoko, travels to Tokyo, a city scarred by previous conflicts. There, they encounter a refugee group called "N" and clash with a hostile U.S. Special Forces team. As tensions escalate over a potential nuclear crisis involving a hijacked submarine, the rivalry among Section 9, the United States, and the Posthumans intensifies.