Sukami Kyouichi comes from a long line of exorcists, and his older sister is a renowned expert in the field. She has meticulously documented her encounters with various monsters in a notebook. While investigating a supposedly haunted shrine with his friends from the Occult Club at school, Kyouichi finds himself in danger and is saved by his sister. However, not long after, she goes missing and is assumed dead, leaving Kyouichi with only the notebook as a clue.
Despite the setback, Kyouichi remains committed to finding his sister and continues to participate in the Occult Club. As he grows older, his search gains traction when a shinigami claiming to be his sister's friend appears...
