In the historical backdrop of Japan's Taisho Era, the brilliant scientist Ayanokoji crafted the Steel Angel, a humanoid possessing extraordinary physical prowess. As the Imperial Army sought to harness this creation for military supremacy, Ayanokoji envisioned a more profound purpose for his invention, leading him to clandestinely bring to life the Steel Angel known as 'Kurumi'. Unexpectedly, a curious young boy named Nakahito Kagura intruded into Ayanokoji's residence on a dare, stumbling upon the inert form of Kurumi. Amidst the chaos of an Imperial Army assault, Kurumi's fall onto Nakahito culminated in a fateful kiss that sparked her awakening, marking the inception of a miraculous bond.