Chise, a fragile and average high school student, finds comfort in her growing romance with her childhood friend Shuuji. Together, they spend their days overcoming trivial problems and conquering the notorious "Hell Hill" before class in their small military town in Hokkaido. Their peaceful existence is shattered when Shuuji and his friends venture to Sapporo to buy gifts for their girlfriends. Tragically, a violent air raid decimates the city, claiming the lives of thousands, including one of Shuuji's companions. This devastating attack marks the start of a brutal war. In the chaos, Shuuji reconnects with Chise, who is no longer the same innocent girl he knew. Her once delicate form is now adorned with metallic wings, and her right limb replaced with a colossal weapon that makes her an ultimate cyborg weapon capable of obliterating entire cities. Despite her objections, she has become a soulless entity devoid of humanity. As the war approaches their hometown, Shuuji and Chise's bond is put to the test. Can he still love her, despite her being nothing but a heartless machine?