Eun-joo goes from her house"Il Mare", leaving a Christmas card for the eventual new owner of the home in 1999. Inside asks him to forwards any mail of hers to her new address inside the metropolis. It is 1997 and Sung-hyun, the very first owner of"Il Mare" is moving and discovers in his mailbox that the Christmas card from Eun-joo. Thinking it had been a joke, Sung-hyun leaves her a letter telling her and reminds her that its 1997 not 1999. Eventually the two realize that they are split by two decades of time but can somehow convey throughout the mailbox and start to form a friendship during their letters.