Natsume's Book of Friends Vol. 23 (manga)

Natsume and his friends stumble into a ghostly treasure hunt when they hear about a haunted painting. His friends are eager to investigate, but Natsume suspects it might involve a dangerous yokai. To protect his friends, Natsume goes along with the quest, but the strain of keeping them in the dark is starting to show. Will Natsume ever be able to tell them the truth?