Yoshimori Sumimura, a junior high student, leads a double life as a 'kekkaishi,' hunting demons by night with his unique skill of erecting mystical barriers. However, by day, Yoshimori faces different challenges - battling his sweet tooth cravings and dealing with his grumpy grandfather. Alongside him is his beautiful 16-year-old neighbor and childhood friend, Tokine Yukimura, also a kekkaishi. Despite their shared talents, their families are embroiled in a feud over who truly holds mastery over this ancient art.