S05E03: The Letter from the Exorcist

Natsume receives a letter from Matoba, an exorcist whom he's had unpleasant dealings with in the past. The world of exorcists is a dangerous place lately, and Matoba wants Natsume's help. Natsume wants to refuse, but Matoba threatens to reveal Natsume's powers to his adopted family, which would spell the end of his peaceful life.