In a tale of half-demon twins, Towa and Setsuna enjoy a blissful life together in ancient Japan until a forest blaze tears them apart. Towa finds herself hurled into modern times, where she is raised by Souta Higurashi. A decade later, Towa, now a 14-year-old high schooler with a penchant for brawls, faces a new challenge when three unexpected visitors from the past appear: Moroha the bounty hunter, demon slayer Setsuna who turns out to be Towa's forgotten sister, and the demon Mistress Three-Eyes on a quest for a mystical artifact. As the trio battles their adversary, Towa is devastated to realize that Setsuna has no recollection of her. Hanyou no Yashahime: Sengoku Otogizoushi tracks their journey to restore Setsuna's memories and untangle the secrets of their intertwined fates.