By night, teenager Yoshimori Sumimura is a "kekkaishi"--a demon-hunter who specializes in creating magical barriers around his prey. By day, Yoshimori's got other demons to battle: an addiction to sweets and a seriously crotchety grandfather! Yoshimori's pretty neighbor and childhood friend, Tokine Yukimura, is also a kekkaishi, but their families are feuding over who is the true practitioner of the art.

The Dark Watchtower, a mysterious group of powerful ayakashi demons, is launching a consolidated assault against Yoshimori's ancestral land. Will Yoshimori, Tokine, and their latest kekkaishi-in-arms, Gen, be able to fend off this all-out attack?!