Associate Professor Akira Takatsuki's Conjecture Vol 6

From the Yen Press edition

Professor Akira’s scary story party became a strange tale itself when a ghostly voice was caught on the recording equipment—now it falls to the professor and Fukamachi to resolve the mystery of the Night of One Hundred Horrors! And Fukamachi’s summer has more in store, with Akira accompanying him to Nagano. There, they will learn the secrets of the festival of the dead that Fukamachi saw on the muggy summer night of his youth that changed his life—and his ears—forever!

Source: Yen Press