Modern man Cheng Yan dies unexpectedly, and his soul is transported to a medieval European-style fantasy continent, where he becomes Roland, the fourth prince of the Kingdom of Graycastle. This playboy prince rescues the witch Anna from an execution and is stunned to learn that magic truly exists in this medieval otherworld.
When Anna demonstrates her magical abilities, Roland realizes that magic can substitute for certain modern technologies, leading him to devise a "great development of magical industry" plan. In an era where witches are universally despised, the independent Roland starts recruiting them, using their magic to remodel Border Town and enhance the lives of both himself and the locals.
Beyond applying magic to industrial development, Roland introduces modern business concepts to Border Town. Under his leadership, people manufacture firearms, and Roland earns the support of the populace. As the number of witches in Roland's camp grows, the magical industry continues to advance. Meanwhile, Roland must confront battles with powerful noble families and rival princes and princesses.
As his territory expands, Roland successfully fosters a peaceful coexistence between witches and ordinary people, gradually bringing the western territory of Graycastle—and eventually the entire kingdom—under his control, while slowly uncovering the secrets of the demon race and the Witch Empire.