Associate Professor Akira Takatsuki's Conjecture, Vol. 5 (manga)

"University student Naoya Fukamachi has the ability to unerringly detect lies. He finds himself working for his eccentric associate professor of folklore studies, Akira Takatsuki, to investigate the supernatural. After closing the case on the eerie mystery of 4:44, the two head to the sea following reports of mermaid sightings. Then one summer evening, they find themselves tumbling into the candlelit horror of 'The Night of One Hundred Ghost Stories!'"--