This is about two girls who were in love with each other. One day, the other girl wanted to study astronomy and it soon happened. She was on her way to meet the girl she likes so they can meet again as there promise to each other but then on her way in the streets of Seoul, she was involved in an accident. She later woke up only for her to be told that she was in a three year coma and that she has amnesia. She was then admitted out of the hospital and started to live her life as an astronomer but one day, during a tour of internship she suddenly remembered something, it was about a girl. Will she remember her and find her or she will not? Even if she did remember her, will she find her?