The male protagonist and the female protagonist met each other when they were young. They were each other's innocent first love. After a beautiful relationship, the two separated due to long distance. We met again in college. The nostalgia for their first love made the two start over, but they could never return to the original beauty. During the three years of separation, the male protagonist's experiences changed his temperament drastically. What happened to him that made him completely different from before? And what's the secret behind why he abandoned the heroine when she was pregnant? At this moment, another outstanding man enters the heroine's world. What choice will she make?