A systems engineer named Matsumoto Yuu and his beloved British Shorthair cat Orihime are suddenly transported from their ordinary life in Tokyo to a fantasy world. Yuu, a divorced and unremarkable thirty-four-year-old programmer, finds himself in a medieval-style land where magic and nobility govern daily life. Shortly after arrival, he encounters Annemarie, a young viscountess from an impoverished noble household struggling to restore her family's territory. Yuu decides to lend his expertise, using his systems engineering background and programming knowledge to analyze and reconstruct lost ancient magic theory. By blending his divine-like problem-solving skill with code logic, he begins developing innovative magical tools that can reshape the region's infrastructure, agriculture, and defense. Alongside his loyal cat Orihime and the warm-hearted people of Annemarie's estate, Yuu works to revive forgotten magical technologies and turn a struggling domain into a thriving territory. The narrative follows his gradual transformation from a solitary office worker into a revolutionary figure in the world of magical toolmaking, while also exploring the bond between a man and his cat as they navigate an unfamiliar world together.