Half-demon twins Towa and Setsuna were always together, living happily in Feudal Japan. But their joyous days come to an end when a forest fire separates them and Towa is thrown through a portal to modern-day Japan. There, she is found by Souta Higurashi, who raises her as his daughter after Towa finds herself unable to return to her time. Ten years later, 14-year-old Towa is a relatively well-adjusted student, despi...