By night, high school student Yoshimori Sumimura is a kekkaishi- a demon-hunter who specializes in creating magical barriers around his prey. By day, Yoshimori's got some other demons to battle: an addiction to sweets and a seriously crotchety grandfather! Yoshimori's pretty 16-year-old neighbour and childhood friend, Tokine Yukimura, is also a kekkaishi, but their families are feuding over who is the true practitioner of the art. Yoshimori and Tokine have successfully vanquished the thousands of butterflies that swarmed on Karasumori High School. But the mystery deepens when the perpetrator of the attack turns out to be a medium that delivers a warning of unspeakable horrors to come! Perhaps some answers lie in the past of Yoshimori's family...