Jeong-kwon Kim

Ji-ho is a promising pianist who has been studying and playing abroad for years, but her career takes a blow when she is struck with stage fright. Returning home, Ji-ho is reunited with her old school friend, Seung-ryong, who, although now in his twenties, has been left with the mind of a six year old following an accident. (wikipedia.org)

The story revolves around the relationship that develops between two college students, So-eun and In, who connect via a ham radio one night. However, when they decide to meet on campus and miss each other, it is revealed that they are separated by 21 years, with So-eun in 1979 and In living in the present day, 2000. Eventually, they become comfortable with the supernatural phenomenon that has brought them together, as well as their correspondence. She relates her camaraderie with her best fri (asianmovieflix.com)

Little Seung-jae stays up all night and writes letters to So-hee, pretending to be her father in Mars. Leaving Seung-jae's innocent heart behind, So-hee leaves for a big city. Both grown up to be adults, Seung-jae is a postman who writes letters to So-hee's grandma - the letters that never came from So-hee. So-hee's heart hardens after hardships in life and she comes back to her hometown and Seung-jae's heart swells up again at seeing her again... (hanbooks.com)

A self-sufficient librarian helps a distraught man search for a message left in a book for him by his former girlfriend. (imdb)