A second goodbye to you.

Harusawa Hinata, who works as a web designer, receives a call that the body of his best friend Sora Otonashi, who disappeared in his second year of high school, has been found.
He attends the wake with his friends from the art club, where Shinohara notices something when he sees a picture Sora drew just before his disappearance. However, Shinohara and Hinata are attacked by someone. When they wake up, they find themselves in "that place" on "that day"!

What is the truth behind their best friend's disappearance and death? And what is the secret hidden in the picture Sora drew?