Saikawa and Nishinosono return to the camp, putting off trying to find a solution to the case. But they can't stop thinking about it. They go back to the lab and investigate Dr. Shiki's rooms again, where they find a strange number that is a clue.
All of them only reach volume 15.
.كلها تصل للمجلّد 15
Alle gehen nur bis Band 15.
Todos llegan al volumen 15.
Todos llegan al volumen 15.
Tout est en quinze volumes.
Arrivano tutti al 15° volume.
Só tem até o 15º 
volume, de todos eles.