I'm the Only One Who Knows

Even though high school student Arima Shougo is truly terrified of anything eerie, because he can see ghosts he was forced to join the "Occult Research Club". In an unexpected turn of events, he encounters the ghost of Yoshizawa Takumi, an underclassman who is rumoured to have committed suicide. Arima helps fulfill Yoshizawa's only wish that keeps him lingering with regret. While doing so, Yoshizawa's kind and gentle personality underneath his calm and collected expression slowly captivates Arima. What will happen on the final day that Arima fulfills that wish completely...?

(Source: Gentosha Comics, translated)

Note: Includes one extra chapter.