By night, junior high 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.

Although Yoshimori and Tokine often quarrel, they battle demons side by side almost every night. When the two must confront demon-charmer Yomi and her dysfunctional pet demon Yoki, their partnership is threatened. Can they work together to keep their school from the clutches of a power-hungry monster-and keep their fellow students from noticing?