Funny how a simple action turns everything upside down.

Na Mirae is just an ordinary 20-year-old girl, trying to survive in the classic orchestra music world. A beautiful lead violinist, with a goal set to Vienna in honor of her dead parents. Nothing out of the ordinary right?

Until one day she noticed a sparkling silver rabbit pin sitting on a bench, where 6 guys were viciously killed in a gang fight a few years ago. Funny how it started oh-so-simple, Mirae picking up the rabbit pin, to get haunted and followed by ghosts. Plural.

She doesn't have 1, or 2 ghosts following her. She has 6, and she - without her knowing - has herself involved in a contract that can't be broken. Now she has 300 days to help these 6 ghosts to transform themselves.                

From ghosts to angels. 

And they only have 300 days.