The Long Nightmare is the 15th volume of Muhyo & Roji's Bureau of Supernatural Investigation manga series.
- Article 122: Teacher & Student
- Article 123: The Knight
- Article 124: What Might Have Been
- Article 125: Lollipop
- Article 126: The Curse
- Article 127: Hades
- Article 128: Falling Down
- Article 129: Some Things Never Change
- Article 130: The Long Nightmare
- Article 131: Crime and Punishment
- Article 132: The Report
Envoy Possession is forbidden by the rules of Magic Law, but Busujima and Umekichi aren't above breaking a few rules to put Teeki on the ropes. Meanwhile, Muhyo and the rest go head-to-head against Enchu, but will they be able to save him from the darkness of his own making?