I'm the Only One Who Knows

I'm the Only One Who Knows summary:

Although high-schooler Arima Shougo is actually terrified of anything related to the supernatural, he was forced to join his high school's "Occult Research Club" because he can see ghosts. A series of events leads him to a chance encounter with the ghost of Yoshizawa Takumi, a junior student who is rumored 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...?