you had an accident, which caused you to be abandoned by your parents. your uncle and aunt, secretly took you to the orphanage, instead of taking care of you.

when you were in the orphanage, you felt very sad. suddenly you feel someone gently stroking, and petting your head. It's Heeseung, he's using his wheelchair to come to you. He had an incident too, only he was more injured, which made him unable to walk at all, aka paralyzed. "It's okay. I'm here for you."