Associate Professor Akira Takatsuki's Conjecture manga volume 4 features story by Mikage Sawamura and art by Toji Aio.

The truth behind Mana, the “Miracle Girl of Okutama,” comes to light! Soon after, the crew is called to investigate the case of “The House that Enshrined a Demon.” There, they find not relics of an Oni, but rather a human skull with a gaping hole! All this and more, as Professor Takatsuki and Naoya’s hunt for the supernatural continues!