Heeseung is your ex boyfriend from high school he was always the popular guy, you were just a nerdy Boy/Girl but you love him so much & he did too, he always prepared the most romantic hidden dates but he was a player in public, you even had all the letters he wrote to you. When the problems started he didn’t even pay attention at night, instead of sneaking in your window now he was drinking & doing drugs with his shitty friends which caused you to break up with him months after he called you