Sun can be seen because of its own light,     when Moon can be seen because it reflects the light from

    Kim Yeonri has a condition about her memory. She can memorize everything but people's face and name. Only a few people who can stay in her memory, and that means that people really important for her. When she's on desperate state after break up with Baekhyun, she met with Kim Taehyung. That boy seems has interest towards Yeonri but she can't remember him. After he knows everything about Yeonri's condition, he swears to himself to make her remember him.