During the day, Yoshimori and Tokine are normal students living a regular school life. At night, they protect the Karasumori site as Kekkaishi. One day, the Ayakashi Tsuchigama invades into the Karasumori school grounds. Yoshimori must run through the Tsuchigama's rain of attacks in order to destroy the Ayakashi.

The Karasumori's power causes Yoki to go out of control. Even Yomi is unable to stop her demon now. Hakudo and Odo, who were sent by the Shadow Organization to pursue Yomi, arrive and destroy Yoki. Yomi is then taken into custody for defying orders. As she departs, Yomi learns from Yoshimori the true meaning of kindness.