In 1983, high school teacher Ji-hwan is attacked by a pickpocket. In 2015, homicide detective Gun-woo is shot during a chase and loses consciousness. Both men are taken to the same hospital in different time periods, and both their hearts stop and miraculously start again at the same time. A mysterious force binds them together, allowing them to see through each other’s lives in their dreams. Soon realizing that the women they love strikingly resembles each other and that they are in fatal danger, the two men must team up to trace the past and change her destiny.
Shy Ji-hae’s friend is having problems expressing her feelings to the boy she loves, so she asks Ji-hae to write e-mails to him in her name. As the boy falls in love with her letters, Ji-hae discovers the story of her mother’s romance which is remarkably similar to her own circumstances.
In Seoul, the paths of two men and one woman intersect and move apart from one another, centering around their love for cinema. A suicidal student meets a young woman who decides to follow him in his fatal gesture. Coming out of a cinema, Tongsu, an unsuccessful filmmaker, spots a beautiful young woman, and recognizes her : she is the main actress in the film he has just seen. The life of this wavering and distressed young man strangely echoes the one of the young man from the beginning…