From Fallen Apples Scanlation:

Yokota and Mishima are art students at a University. One evening, everyone goes out drinking and Mishima ends up in a car accident. Taken to a hospital, his body is on the brink of death. But, his soul pops out and ends up trapped in a studio room at the University. He won’t die because there’s still something keeping his soul connected to this world. Yokota is the only one able to see and touch him, so he has to help Mishima put his soul to peace.