Umehiko and his younger sister Momo are suddenly transported to another world by a mysterious magical seal. Umehiko manages to send Momo toward safety but is left stranded, where the powerful sorcerer Theodorus declares that Umehiko will take the place of the “blessed maiden” he intended to summon. Bound together by an unwanted magical arrangement, Umehiko must navigate this unfamiliar world while searching for a way home.