In the kingdom of Earlshide, Merlin Wolford was once regarded as a national hero, hailed for his power and achievements. Preferring to a quiet life, however, he secludes himself deep in the rural woods, dedicating his time to raising an orphan he saved. This orphan is Shin, a normal salaryman in modern-day Japan who was reincarnated into Merlin's world while retaining his memories. As the years pass, Shin displays unparalleled talent in both magic casting and martial arts, much to Merlin's constant amazement.

On his 15th birthday, however, it becomes apparent that Shin only developed his combat skills and nothing else, leaving him with blatant social awkwardness, a lack of common sense, and a middling sense of responsibility. As a result, Shin enrolls in the kingdom's Magic Academy to hone his skills and mature among other teenagers. However, living an everyday life is impossible, as he is established as a local celebrity almost as soon as he arrives.

As Shin Wolford adjusts to his high school life in the capital, he makes new friends, learns about the world, and fights off the various forces of evil surrounding him and his city.