Hanna, an overweight lip-sync artist who ghost sings for Ammy, a known pop diva, secretly likes Han Sang-jun. When Ammy humiliates Hanna in Han's presence, Hanna decides to undergo a cosmetic surgery.
An assistant to a TV producer, eager to stay off his bad side, promises to convince her former professor, a famous but reclusive academic, to appear on their show, which helps locate long-lost persons. Who does grey-haired Professor Yun Suk-Young want to see again more than anything? The answer to that question lies decades in the past.
In the year 1999, a young woman leaves her quaint seaside house and returns to the city, leaving in the mailbox a card for the next owner, with instructions to forward any mail of hers to the new address. In the year 1997, a jaded young architect moves into the same house and finds the letter. His reply, which he slips into the mailbox, finds its way to her, beginning a parallel-time love story separated by a span of two years.