Shin Jae-joon / Yuu (Hero Jae-joong) was involved in an accident that put him in a coma. Now, his spirit has the ability to travel back and forth to the afterworld and the real world. He delivers letters to heaven from those who can't get over the loss of their loved ones. One day, he meets Jo Hana / Saki (Han Hyo-joo) as she is trying to send her boyfriend a letter, discovers Jae-joon's secret identity.  Hana, however, is the only person who can see Jae-joon. He offers her a part-time job assisting him, and they set off on a 14-day journey.