High school girl Ran becomes an outcast overnight after being involved in a scandal in school. The only person left that still talks to her is a ghost named Chen. Twenty years ago, Chen and his classmate Jin had committed suicide there out of their love for each other. And ever since then, Chen has been trapped on that rooftop, helping people travel back in time and fix the things that they regret. When Chen’s ghost suddenly disappears, Ran makes a wish to see him again under the full moon – having grown quite fond of him. But when she wakes up the next morning, she discovers that not only has she travelled back to the day Chen killed himself but that she’s inhabiting Jin’s already-dead body. She tries to stop Chen from committing suicide, but much to her surprise, she learns that he and Jin were never even close. Things grow all the stranger when Ran and Chen become trapped on that same exact day. As Jin’s physical body deteriorates, Ran must solve the mystery of their deaths to free herself from this endless cycle – all while the looming question remains: does Chen have to die for Ran to live?