Overview
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...
| Actor | Age then | Age now | |
|---|---|---|---|
 | 28 | 51 | |
 | 25 | 48 | |
 | 32 | 54 | |
 | 26 | 49 | |
 | 25 | 47 | |
 | 30 | 52 | |
 | 32 | 54 |