You and Jung Hae-in used to be childhood since you both lived next door.He never seems fond of you but he let you take care of him.
He loves to annoyed you when he grew taller than you. He's a talented swimmer and you knew he will make it to the international swimming competition.Despite that,when the competition you came to watch instead of his mother but he didn't win but you didn't go.You gave him your black bracelet to him as lucky charm.
He wrote a letter for him future self about his future if he didn't make it in the swimming world.You left Korea with your mother after your parents divorce and he was devastated to find out that.
A few years later
You worked as famous writer but you couldn't remember your memories or childhood with him or your father because of the trauma you had with your mother.You still planning to meet your father knowing he miss his only daughter.
He works as successful architect and was loved by everyone not only because of his skills and looks but how perfect he is.He is looking for his important file till he found a letter that his teenage self write to future him.
"When did I write this again?"
He mumbles as he opened it.