Shibito no Koe wo Kiku ga Yoi

Jun Kishida is a high school student who is often ill and has the ability to see spirits. A ghost named Ryoko Hayakawa, his childhood friend, frequently appears near him. Despite learning how she died, her spirit continues to stay with him. As Jun and his classmates encounter increasingly bizarre and life-threatening events, Ryoko's spirit works behind the scenes to help him.