Shin Jae-joon (played by Jaejoong Kim) is an IT elite. He is successful in his career and has a flamboyant personality. Because of a car accident, he became a vegetable. God gave him two weeks of life as a condition to let Jae-joon serve as a postman in heaven. Jae-joon travels back and forth between heaven and the human world to deliver letters, bringing hope of survival to people who have lost their loved ones, and his understanding of love gradually changes and becomes profound. Zhao Hena (played by Han Hyo-ju Han) can't let go of the death of her lover, so she always mails letters full of resentment to her dead lover. The two met at the heavenly mailbox on the grassland by chance. By chance, Jae-joon decided to let Hena serve as his assistant in the human world. In the days of sending letters with Jae-joon, Hena gradually came out of the shadow of her past feelings and gradually fell in love with Jae-joon. At this time, seeing that Jae-joon's two-week life span has expired...