In the summer of 1998, the lively and frank girl Xia Mo got to know the boy Yun Shiye, who was far away in Linshi city, through an accidental pen pal activity. One came from a small county town, and the other lived in a bustling metropolis. The two shared youth, dreams, and growth through a series of letters. Xia Mo worked hard to pursue a key high school, and Yun Shiye patiently shared study insights, making progress together in mutual encouragement. As school life unfolded, they also harvested precious friendship and unforgettable youth memories.