At night, junior high school student Yoshimori Sumimura is a "kekkaishi"—a demon hunter who specializes in creating magical barriers around his prey. During the day, Yoshimori faces other demons to battle: an addiction to sweets and a seriously crotchety grandfather! Yoshimori's pretty 16-year-old neighbor and childhood friend, Tokine Yukimura, is also a kekkaishi, but their families are feuding over who is the true practitioner of the art.